The Anatomy of Chlamydoselachus 453 



Concerning the external anatomy of the myxopterygium of Chlamydoselachus, 

 Goodey (1910.1, p. 564) states that: 



On the dorsal side of each appendage, bounded by muscles, is the channel, which, 

 toward its posterior end, becomes somewhat lateral in position and is bounded here by the 

 knife-edged, movable terminal cartilages T.d. and T.x;. [my Figure 22, plate V]. In a ventral 

 aspect [my Figure 23, plate V] the most prominent feature of the appendage is the glandular 

 sac [S] and compressor muscle, covered with loosely fitting, soft skin. The skin covering 

 the sac and the termina Iparts of the appendages is very soft and is entirely free from 

 dermal spines. 



For a more comprehensive description of the claspers of Chlamydoselachus, we are 

 indebted to Leigh-Sharpe (1926) whose account is illustrated by my Text-figures 95 to 97, 

 and 115 (p. 472). From Leigh-Sharpe (pp. 308-311) I quote as follows: 



This genus [Chlamydoselachus], though included from other characters in the Proto- 

 selachii, does not show any affinities with J^otidanus in its copulatory organs. The claspers, 

 far from being primitive, are long, tapering, and somewhat slender, though possessing strong 

 skeletal supports, 13 cm. in length in this specimen, and devoid of dermal denticles (Fig. 1) 

 [my Text'figure 95]. The clasper groove is long and closed for the greater part of its length 

 (Fig. 2) [my Text-figure 96a], and the apopyle is small. The apex of the clasper is capable 

 of expansion or erection, like a bivalve shell, the larger valve acting as a cover rhipidion. • 

 The true rhipidion may be represented by a small protuberance, not far from the apex, which 

 contains a separate cartilage, and is discernible in figure 5 [my Text-figure 115a, p. 472]. On 

 this occasion the animal's left clasper has been dissected instead of the right as heretofore. 



There is no siphon present, but situate on the inner ventral aspect of the proximal end of 

 the clasper is a large cavity which opens dorsally by the clasper groove of which it forms an 

 expansion. In these two characters a startling similarity is shown to the Holocephali, more 

 expecially to Rhinochimaera, and, as I was unable to dissect the latter, the details of the 

 present type are portrayed more fully. 



The cavity, which occupies roughly three-quarters of the length of the clasper parallel 

 with the clasper groove, is much distended, with powerful muscular walls, supported by 

 two radial cartilages outspread in a fan-wise manner (Figs. 4 and 5a) [my Text-figures 97 

 and 115a]. I have no doubt that it can be used for pumping spermatozoa, being, therefore, 

 analogous with a siphon; and in this it agrees with the cavity of Callorhynchus and Rhino- 

 chimaera, though not with that of Cestracion (which possesses a siphon) and some species of 

 Chimaera. When the claspers are anteroflexed as in copula (Fig. 2) [my Text-figure 96], the 

 cavity collapses and is compressed. By a comparison of measurements, it seems certain that 

 the posterior part of the cavity must be included in that part of the clasper which is introduced 

 into the oviduct of the female. 



The simplicity of the clasper has prompted a more detailed account of its anatomy. 



Regan (1906.2, p. 740) states that the myxopterygium of Chlamydoselachus and the 

 notidanids is a more primitive structure than that of the galeoid sharks. 



THE ABDOMINAL PORES 



Although there is no immediate evidence that the abdominal pores have anything 

 to do with the urogenital system, it is convenient to consider them here, since they are 

 situated near the urogenital sinus and are often figured with it. 



