HERBERT 1 2 . RATCLIFFE ,4ND H E L E S 1)EAN 1CLL(; The TF’iilur Institute of Aiiatoiiiy and Rzolopy and Dcpnrtrnciit of Putliology, 77nzrer.szt.tl of Prnitsylzunia, Plriladelpliza FOVR FIGURES The anomalous nialc here reported appeared in the st rain of inbred albino rats that has been maintained at The Wistar Institute since 1909. It belonged in a litter, comprising two males aiid five females, born December 28, 1938. Litter i r i ~ t e s and tlie forty-seven other ofispriiig of tlie same parents were normal. Somcwliat smaller than other members of the litter at birth, this abnormal male grew very slomly during t l ~ c suclding period, but otherwise seemed healthy and moved actively about the cage until it TVRS about 45 days old. Tlieii signs of pulmonary suppuration appeared and the abdomen became so clisteiiclcd by the developmeiit of several firm, irregular masses that locomotion was difficult. As death seemed imminent, the rat was killed when 56 (lays old. At this time it had a body weight of 111 gin., the weight of a normal litter brother being 187 gm. 9 “cloiible monster’’ had never been found previously iimong the inbred albinos, althougli over 70,000 r a t s liad been born in tlic strain. It seemed possihle, therefore, that this unique individual might be a mutant type, not recorded for the rat, although known to occur in mice where heredity seeniiiig1.iplays an important role in its development (Danforth, ’30). Wlicii iiiature, normal litter mates of this aiiornalous rat were inbred, as were a number of their descendants through t h e e generations. All of the young, approximately 200 individuals, were nornial. This finding indicates that the malfoi*inationwas 19 50 11. L. KATCLIFFE A N D H. TI. K I N G not of geriiiiiial origin, but a sporadic case that can be interpreted, iii accordance with Stockard’s ( ’21) view, as due to some unfavorable intrauterine condition ~ l i i c l lcaused an arrest or slowiiig of its developmental rate dnring a particular period of foetal life. Head, thorax and anterior extremities of this animal were perfectly formed. Suspended from the anterior abdominal Fig. 1 Tenti a1 view showing tlirce liiiidleg~ uiid the inipcrfect forcleg that deve1oT)ed from thc :ibdoininal wall. The 1ii:iss to tlrr left of tlie mid-line is p:wt of the fourth hindleg. The bulging lower abdoineii is slioivii. wall was a narrow, flaccid, tulmlar structu1.c which terminated in an incompletely dercloped forefoot (fig. 1). The right hiidleg was about twice normal di;imeter throughout its length and divided longitudinally just above the ankle into two u11equal halves each of which carried a complete foot. l’he lateral one of these feet furictioiied as the right foot of the animal, while the median one, a left foot, w a s fully flexed, curved INCOMPIJETE POSTERIOR DUPTJCATION 51 slightly towards median line of the pair, and fixed in position. The functional left liindlcg was eritircly nonnal, but to the left of the anterior mid-line, loosely joined t o the pubic region, was a single, complete right hinclleg. This was so placed as to drag 011 its lateral surface, but could be moved into alniost Fig. 2 Dorsal view with the Iiiiidlegs :nid tail in the usual l)ositions when t h e anillla1 was free. any positioii. Whetlier or riot voluntary rnotioii of this member TWS possihle is uiiknowii. In a n y event, it appeared wasted or nridei.-developcd (fig. 2). Tlie iritcrnal structures of the head, neck, and t11oi.n~were not unusual except for scattei.cd lobular consolidation of thc 52 If. I,. IIATCLIFFE ANT) H. n. KING lungs. Likewisc tlie liver, splecii, paii(was, stomach, kidneys aiicl ailiwials lincl developed normally. But, about 4 em. distal to tlic stomach, a sliort portioii of the small intestine was moderately expriclecl arid beyond this point the entire iiitestiiiirl tixct was dnplicatetl. From tlie miicous surface of tlic intestine, tlie division was less abrupt tliaii iiiclicated by cxteixal appeal-ances. Iiiteriiallp tlic separation began well al)ovc tlie point a t wliicli the s e r o ~ ssurfaces divided, and Fig. 3 Dingraniiliatic sketch of a b d o n ~ i ~ ~: a~ln d 1)rlric viscera. Outlines of the Iiiiidlrgs ;ind toil parinit orient:ition, 1)ut cwtnin org:ins w e w (1ispl:tced so th;it aiiatomicnl arrairgeiiients could ~ J Cslio\vn. See teat f o r description. (Appmxiiiiatelg natural size.) tlie tubes were u i i q u i d , the k f t Iwiiig Iwi*gclrand its ostiuiii wider (fig. 3 ) . Tlie left brancli of tlic iiitestiiie connected with R normal cecum, eoloii aiid amis i n ~vliichthe contents were of the usual cliaraclei~. Tlie riglit l)imic11of the siiiall intestine also joined a cecum and eolo11, bnt the cecum and distal half of tlic large in t es ti11c we rci di stencl(d bv twmpac t etl fecal mass c s ~ 1 1 quantities of irioi*pinic crystalliiie matcirial. ~ 1 I N C O M P L E T E POSTERIOR D U P L I C A T I O N 53 The expanded terminal right colon and rectum were densely adherent to pelvic surfaces at various points and, in the perineal region, had almost perforated into the subcutis. Dense adhesions also bound the distal end of this segment of the gut to a larger thick-walled Idadder-like structure which was placed in the anterior mid-line above the pelvic brim. The right rectum emptied into the neck of this viscus by a small circular opening about 1mm. in diameter. The mucosa of this bladder, of its opening into the rectum and of the rectum was continuous and intact. The neck of this bladder opened into a thin-walled tube of irregular diameter, the lumen of which expanded into three saccular diverticulae, the last just above the penile urethra, with which the tube was continuous (fig. 3). Surrounding this irregularly expanded channel were dense masses of inflammatory tissue. This bladder-like structure and the sacculated tube contained material similar to that in the expanded colon. To the left of the large bladder lay the smaller, normal, urinary bladder, attached to it by thin, membranous tissue. Normal ureters, arising in the two normally formed and placed kidneys, entered the neck at the usual position. Rudimentary seminal vesicles and prostate lay dorsal to the neck of the normal bladder which continued as a thin-walled tube (membranous portion of urethra?) t o join the channel leading to the penis (fig. 3 ) . The penis was in the normal position, but small, apparently underdeveloped. Bulbourethral glands were not found. Placed at the left of the tail’s base a small scrota1 sac contained a normally formed but small testis, from which the ductus deferens passed through the inguinal canal to join the urethra. On the right was found another small testis, placed in a thin-walled subcutaneous sac on the medial surface of the doubled right thigh, nearer the knee than the groin. The duct from this body passed dorsal to the distended right colon and central bladder to the urethra. The spermatic arteries for this pair of gonads were traced to the aorta (fig. 3). 54 €I. L. R A T C LI F F E A N D H. D. K I N G Attached by a short, broad mesentery to the lateral wall of the distended right large intestine were two spherical pale, ivory-white bodies 4-5 mm. in diameter and supplied by blood vessels from tlie wall of the gut. These were taken to be a second pair of testes. Opaque material in the blocked half of the intestine and in the central bladder obscured roentgenograms of the pelvic bones, and the bones of tlie hindlegs were too complex in their arrangement to allow suitable views. Therefore details of Q A B C D Fig. 4 ( A ) Bones froin appendage attached to abdominal wall. (B) Median aspects of right pair of innominate bones. ( C ) Ventral aspects of pelvic and adjacent vertebrae. (D) Ventral aspects of lcft pair of innominate bones. the skelton were studied after the body had been clcareci and stained under the direction of Dr. E. J. Farris. Tlie spinal column was not abnormal except for minor variations in the contours of the lateral processes of the vertebral bodies. The pelvic skeleton consisted of a single sacrum to which was attached two pairs of innominate bones (fig. 4, B, C and D). One ileum of each pair seemed fully developed, and articulated with the sacrum. The right pair of innominate bones, sketched in figure 4,R, from the median aspect, formed INCOMPLETE POSTERIOR DUPLICATION 55 a sharply angular and abnormally long symphysis, the apex of which pointed to the mid-line of the animal. I n the riglit half of this pair the pubic bone was short and heavy, the ischium moderately distorted and the ilium approximately normal. I n the left half, lack of development of the ilium was particularly notable, while other elements were nearly normal. Acetabula had formed in the usual position, and tlie femora articulated normally. These were approximately equal in length, but the median one of the pair measured about half its fellow's diameter. The bones were not joined, although closely placed a t the distal ends. However, the tibiae fused a t the epiphysis and through the upper third of the shafts, but otherwise had developed completely. The fibulae, on the other hand, did not, a s is normal for the rat, fuse with the tibiae, and each was lateral to the companion bone, offering further proof of the opinion that right and left legs made up this complex. Bones of the right functional foot of this pair were complete, but tarsals of the left foot had fused. Of the left pair of inmominate bones (fig. 4, D) the dorsal or left half seemed complete, while the right or ventral half was smaller and tlie ilium distorted into a horn-shaped structure. The symphysis had not fused, although the pubic bones were joined by a cartilaginous band. Acetabula also had formed in this side, and bones of the legs were complete, although those of the median, or right leg, were delicate and tlie shaft of tlie femur had been fractured and separated in the proximal third. The tubular structure that was attached to the anterior abdominal wall contained one narrow, elongate bone, the proximal end of which formed a flattened, subterminal bulb. Possibly this was a humerus. Articulating with its distal end was a group of short, thin bones, forming a sort of socket with it and ending in malformed digits (fig. 4, A ) . Duplication of parts of the posterior region of the body has been variously classified. The present case corresponds t o dipygus of Wilder. ('04), whose material was taken mainly 56 H. L. RATCLIFFE A N D H. D. KING from congenital deformities of man. Usually doubling of the posterior extremities is associated with bifurcation or duplication of the genitalia, the large bowel, and the spine to or above the lumbar segment (Ballantyne, '04; Wilder, '04; Schwalbe, '07). Only three cases of dipygus have been described in rats, one by Conrow ( '17), one by Altman ( '26) and the present one. The spine in each of these was single, although deformities of the hindlegs and internal organs were essentially similar to those found in analogous forms of monstrous development described for other species. LITERATURE CITED ALTNAN,F. 1926 Eiii Fall von Hypogastrius Parasiticus bei einer Ratte (Duplicatus Asymmetras ventralis infraumbiliealis Sehwalbe'). Ztsch. f. Anat. u. Entwiriekl., vol. 79, pp. 413-432. BALLANTYNE, J. W. 1904 Antenatal pathology. Wm. Green and Son. Edinburgh. ("ONROW, S. B. 1917 A six-legged rat. Anat. Rec., vol. 12, pp. 365-370. DANFORTH, C. H. 1930 Developmental anomalies in a special strain of mice. Am. J. Anat., vol. 45, pp. 275-287. SCHWALBE, E. 1907 Die Morphologie der Missbildungeii des Menschen und der Tiere, Teil 11, Die Doppelbildungen, Fischer, Jena. STOCKARD, C. R. 1921 Developmental rate and structural expressions: an experimental study of twins, 'double monsters" and single deformities, and the interaction among embryonic organs during their origin and development. Am. J. Anat., vol. 28, pp. 115-277. WILDER, H. H. 1904 Duplicate twins and double monsters. Am. J. Anat., vol. 3, pp. 387-472.