The Anatomy of Chlamydoselachus 449 



gland mentioned by Garman ] 1885.2] was found in the specimen examined. Passing from 

 the oviducal glands, the oviducts regain their original diameter, but the walls are smoother, 

 the laminae being reduced to slight striae. When the oviduct reaches the level of the anterior 

 end of the colon, it enlarges. The enlargement is gradual and only increased in diameter about 

 fourfold on the left side, but on the right the enlargement is sudden and very apparent, the 

 diameter increasing 14 to 15 times. This region in addition to being enlarged has folded 

 walls, in which occur one large and several small areas of dilated blood-vessels. The largest 

 blood plexus occupies about one-third of the right side of the oviduct. In connection with 

 each plexus, on its dorsal side, the oviducal wall is thickened over an area which equals the 

 plexus in length and breadth. The enlarged vessels apparently supplied these thickened 

 areas. The condition of the oviduct thus described suggests that this portion of the oviduct 

 acts as a functional uterus, and that therefore Chlamydoselachus produces the young alive, as 

 suggested by Garman. The final portion of the oviduct, which succeeds the uterine, has 

 smooth walls and a large diameter, the latter gradually diminishing towards the cloaca. 

 This region divides the functional uterus from the cloaca, thus functionally representing the 

 the vagina of higher types. The opening of the right enlarged oviduct [Text'figure 90a, R.Ov. ] 

 has acquired a median position, the left oviducal opening [L.Ov. ] lying cephalad to it. 



Deinega's (1925) small half-tone figure of the abdominal viscera of a female Chlamy- 

 doselachus is printed on unsuitable paper, so that details are obscure. It is chiefly remark- 

 able in that it shows a complete right uterus which is even larger than that of my specimen 

 No. II. Its length, including the part bulging anteriorly, is equal to about five-sevenths 

 of the length of the body cavity. It is somewhat kidney-shaped, with a maximum width 

 of more than one-fourth its length. The left oviduct is not conspicuously enlarged in its 

 uterine portion. 



Hawkes's observations on the presence of vascular plexuses in thickened portions 

 of the uterine wall suggest a physiological relation between the maternal tissues and the 

 young. I do not know whether the young are carried after the exhaustion of their store 

 of yolk. It seems Hkely, however, that the young sharks are born as soon as, or even 

 before, the yolk is entirely utili2,ed. The largest known intra-uterine specimen, taken by Dr. 

 Bashford Dean, was a well-formed shark, 390 mm. (15.35 in.) long, yet its yolk sac meas- 

 ured 100 X 70 mm. Additional data are given by Gudger and Smith (1933, pp. 298-301). 



It is unnecessary to review the evidence that the genital organs of the right side 

 alone are functional in the female Chlamydoselachus. There is not a single known instance 

 of complete development of the reproductive organs of the left side. Yet it must be borne 

 in mind that the number of specimens that have been described is still very small. The 

 organs of the left side are developed to such a degree that they can scarcely be called 

 rudimentary. In view of the great variability found in many other organs of Chlamy 

 doselachus, one should not be surprised if the examination of additional material should 

 reveal cases in which the genital organs of the left side, or of both sides, are functional. 



In the adult female Heptanchus as described by Daniel (1934), the general plan of the 

 oviducts is much the same as in the immature female Chlamydoselachus. According to 

 Daniel "the oviduct ... is not so greatly enlarged in Heptanchus as in many other Elasmo- 

 branchs in which it forms the conspicuous uterus." In the absence of any definite state- 



