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Bashford Dean 'Meynorial Volume 



Hawkes (1906, p. 983) states that in Chlamydoselachus the anterior cardinal vein 

 lies in the vicinity of the vanished seventh gill-cleft, though in most elasmobranchs it is 

 in the position of the missing sixth gill-cleft. 



The claspers of Chlamydoselachus have been studied comprehensively by Leigh- 

 Sharpe (1926). His Fig. 5a-c (my Text-figure 115a-c) shows the endoskeleton, certain 

 muscles, and the venous sinuses of the claspers. His Figures 5a and b have been referred 

 to in the sections on the endoskeleton (p. 376) and muscular system (p. 395) respectively. 

 The venous sinuses of the claspers of Chlamydoselachus are described by Leigh-Sharpe 

 (1926, pp. 312-313) as follows: 



The main blcxDd-vascular system is composed of 

 two venous sinuses, parallel to, and on either side 

 of, the myxapterygium (Fig. 5c) [Text-figure 115c], 

 in connection with which no erectile tissue could 

 be discovered. 



The inner [sinus], which is the longer and more 

 superficial (Figs. 4a [my Text-figure 97a, p. 452] and 

 5c [my Text-figure 115c]), arises posteriorly in the 

 distal third of the clasper, and, surrounding the 

 clasper muscles, ends blindly in the middle line 

 anterior and ventral to the cloaca. Dorsal to the 

 myxapterygial articulation it cotmnunicates with 

 the other, more lateral, deep-seated sinus; the latter 

 drains blood from the extra-cloacal region and from 

 the edges of the clasper and, continuing forward, 

 empties its contents into the iliac vein dorsal to the 

 basipterygium. Five nerves, proceeding to the pel- 

 vic fin and clasper, traverse this sinus, and also a 

 space (apparently lymphatic) between it and the 

 abdominal muscles. These structures are seen dis- 

 played in Fig. 4b [my Text-figure 97b, p. 452], and 

 the entire venous system in Fig. 5c [my Text-figure 

 115c]. As stated above, the function of the blood- 

 vascular system in Chlamydoselachus does not appear to be that of erection, nor would the 

 metaboHsm of the muscles supplied by it warrant so extensive a system of vessels. Possibly 



Text-figure 115. 

 Claspers of Chlamydoselachus in ventral as- 

 pect: A, the cartilages; B, the musculature; 

 and C, the venous system of the clasper. 



a.m., anteroflexor muscle; Ap., position of apopyle; 

 C!., cloaca; Er.M., erector or expansor muscle; i.v., 



iliac vein; V.S., venous sinus. 



After Leigh-Sharpe, 1926, Fig. 5. 



the sinuses are required to provide easy play for the muscles in the position of antero-flexion. 



THE NERVOUS SYSTEM 



Although some careful work has been done on the nervous system of Chlamydo- 

 selachus, much remains to be accomplished before a satisfactory account can be written. 

 The brain has never been adequately described, even superficially, and the spinal cord 

 has been ignored. The functional analysis of the cranial and spinal nerves is incomplete. 

 Save for some references to the ciliary ganglion, the sympathetic system has been wholly 

 neglected. Lack of time and suitable material prevents my attempting to remedy any of 

 these deficiencies. 



