The Anatomy of Chlamydoselachus 



491 



based on their innervation. Concerning 

 certain sensory canals of Chlamydoselachus 

 Carman (1888, pp. 82 and 83) writes : 



The aural [supratemporal] canal is closed. 

 It has no tubules. Contrary to what obtains 

 in other Galei, it lies in front of the so-called 

 ear openings [endolymphatic ducts]. These 

 openings, however, are at the ends of tubes the 

 inner extremities of which are in front of the 

 [supratemporal] canal. The canal is nearly 

 straight, bending slightly forward in the middle 

 and a little backward near each end. . . . At 

 the end of the jugular, near the middle of the 

 first branchial aperture, there are two branches 

 not found in any other of the sharks examined : 

 a spiracular [HLC in Figure 29, plate VII], 

 turning upward and forward toward the spir- 

 acle; and a gular [HLB in Figure 29, plate 

 VII], turning down and forward near the 

 median line, and finally uniting with the oral 

 [HLA in Figure 29, plate VII] a short distance 

 from the inner end. . . . Apparently the pre- 

 nasal is reversed in direction, meeting the nasal 

 in front and running backward to join the sub- 

 rostral. . . . Like the corporals, the oral, gular 



Text-figure 128. 

 Variations in lateral line canals of Chlamydo- 

 selachus; A and B, supratemporal or commissural 

 canal; C and D, ventral view of hyomandibular 

 canal under the lower jaw; E, lateral Hne canal 



in the region of the dorsal fin. 

 CCA. and C.C.B., anterior and posterior portions of com- 

 missural canal; H.M., parts of the hyomandibular canal; 

 L.L.R. and L.L.L., lateral canal on right and left sides. 

 S., vestigial canals (?). 

 After Hawkes, 1906, Text-fig. 140. 





tS^^^ 



Text-figure 126. 



Text-figure 127. 



Portions of open lateral line canals in a living and 



in an extinct shark. 



Text-figure 126. The open lateral line canal in 



the tail region of Chlamydoselachus. Note the 



elongate scales (x 5) which partially cover the 



open canal. 



After Garman, 1885.2, Fig. 10, pi. VI. 



Text-figure 127. Lateral line canal of the fossil 



shark Ctenacanthus dark}, showing the enlarged 



denticles at the margin of the groove. 



After Dean, 1909, Fig. 44. 



and spiracular [canals] are open grooves. 

 In the spiraculars and gulars of this shark 

 are found the nearest approach to the pleu- 

 rals of the Batoidei. 



Hawlfes (1906) states that the lateral 

 line system of the head of Chlamydosela- 

 chus is much more complicated than is 

 usual among elasmobranchs (excepting rays 

 and skates). Evidently, she refers merely 

 to the gross pattern or topographical 

 relations of these canals. The supratem' 

 poral or commissural canal in Chlaynydo- 

 selachus is placed anterior to the openings 

 of the ductus endolymphaticus, and is 

 never the usual straight, transverse line 

 connecting the right and left lateral canals. 

 It varies greatly, as shown in her Text-fig. 

 140 (my Text'figure 128a and b). There 

 are indications of two instead of one com- 



