542 Bashford Dean Ts/Iemorial Volume 



shows, enable one at a glance to distinguish the male. The claspers are necessary because 

 impregnation in all sharks is internal. These myxopterygia are the only reproductive 

 structures of the male that we need consider here. For elasmobranchs in general, they 

 have been admirably described by Leigh^Sharpe, (1920, p. 245) from whose article I quote 

 the following: 



. . . the basal element of each pelvic fin (basipterygium) is prolonged to form a stout 

 backwardly directed skeletal rod supporting a portion of the fin which is demarcated from 

 the remainder and specially modified to form a copulatory organ, the clasper or myxoptet' 

 ygium . . . The clasper is rolled up in a manner resembling a scroll [Text-figure 6] so that in- 

 stead of being a groove, as it is usually described, it is a sufficiently closed tube along the 

 greater portion of its length, though the edges may not be and usually are not completely 

 fused but overlapping. This tube is one along which spermatozoa pass. 



Not only do the claspers serve as intromittent organs, but inserted into the cloaca 

 of a female they help hold her fast during copulation. Their appearance in lateral view of 

 a male Chlamydoselachus is shown in Text-figure 5 and of another in Figure 53, plate VI. 

 In Text-figure 6, we see these roUed-up organs in ventral aspect with the cloaca between 

 their bases. No further description is necessary here. 



Text-figure 7 

 A 1510-mm. female Chlamydoselachus, whose enlarged abdomen is due to the presence in her ovaries 

 of 10 eggs measuring 80 — 83 mm. in diameter, as seen in Text-figures 3 and 9. Note the absence of 



any external secondary sex characters. 

 Photograph by courtesy of Fumio Momose. 



REPRODUCTIVE ORGANS OF THE FEMALE 

 CHLAMTDOSELACHUS 



The female frilled shark (Text-figure 7) has no external secondary sex characters, but 

 when the ovarian eggs approach ripeness or particularly when the uteri are filled with 

 huge eggs undergoing development, the distended abdomen indicates pretty clearly the 

 sex of the fish even though the pelvic fins are not distinctly visible. Thus all the repro- 

 ductive organs of the female, the ovaries and the oviducts(with their various subdivisions), 

 are internal. They have been thoroughly described by Smith (1937) in the article dealing 

 with the anatomy of Chlamydoselachus, but it will be necessary to consider here certain 

 features having to do with viviparous reproduction in this fish. These are: first, the 

 enormous size attained by the eggs while still in the ovary; second, the great distention 



