374 



Bashford Dean lAemorial Volume 



Text-figure 43. 

 Dorsal view of the right half of the peKas, and of the right pelvic fin, of a female 



Chlamydoselachus. 

 htd., distal s^ment of the basipterygium; htp, proximal segment of the basipterygium; In/, longitud- 

 inal row of foramina for nerves; pg, pelvic girdle; r, lateral radial s. 

 Redrawn from Goodey, 1910.1, Fig. 19, pi. XLV. 



(1885.2) -^Tites: "'The peculiar shape of the pehas suggests an embryonic character of 

 other sharks. In embr^'os the peMs is longer than in the adult, in comparison w^ith the 

 transverse measurement. An embr^^o of Heptahranchias before me has it half as long 

 as \^-ide. proportions which are intermediate between those of the adult and an adult 

 Chlamydoselachus." From another point of view one may say that an elongate pelvis 

 is in keeping Vv-ith the general body form of Chlamydoselachus. 



Carman's figure reproduced as my Text-figure 

 89 (p. 434) is a ventral view, and shows a wedge- 

 shaped piece inserted, at the anterior margin, between 

 the two paired portions of the pelvis. Thus the median 

 suture becomes Y-shaped. This wedge-shaped carti- 

 laginous element is not shown in Carman's figure re- 

 produced as my Text-figure 42, which is a dorsal view 

 of the pehris, presumably of the same female ; nor is it 

 shovvTi in any other published drawing of the pehns of 

 Chlamydoselachus, male or female, dorsal or ventral. 

 Apparently, it is an individual variation. Deinega's 

 drawing (1909, 1923) shows a median groove or suture 

 extending the entire length of the pehris. 



Along the lateral margins of Deinega's drawing 

 of the pelvis, at regular intervals, there are faint trans- 

 verse grooves pierced by foramina, marking off seg- 

 ments in line x^nth the radials. These transverse 

 grooves indicate a metameric origin of this portion of 

 the pehds, presumably through the fusion of primitive 

 radials to form basals which were later added to the 

 pehds. The manner in which basals of the pehnc fins 

 may be derived from radials is illustrated by Dean's 



Text-figure 44. 



Pelvic fin and girdle of the fossil shark, 



Cladosehche \epleri. 



b, basals; p, pelvic arch. 

 After Dean, 1909, Fig. 18. 



