The Anatomy of Chlamydoselachus 357 



ulation with the posterior upper labial it extends forward, along the ventral edge of 

 the mouth, strongly attached to the inner surface of the dermis of the lower lip (AUis, 

 1923). The presence of a mechanism for strengthening and mobili2;ing the soft tissues 

 at the angles of the mouth supports my contention that Chlamydoselachus seizes and 

 swallows large prey. 



Text-figure 24. 



Ventral view of the visceral skeleton (three-fourths natural size) of Carman's first specimen 



of Chlamydoselachus. The branchial rays are omitted from all arches except the hyoid. 



b-br, basibranchial; b-hy, basihyoid; br-r, branchial ray; c-br, ceratobranchial; c-hy, ceratohyoid; e-br, epibranchial; h-br, 



hypobranchial; m){, mandible or Meckel's cartilage; p-hr, pharyngobranchials. 



After Garman, 1885.2, PI. IX. 



The homologies of the labial cartilages of elasmobranchs are obscure. Pollard (1895) 

 considered the labial cartilages to be the remains of the skeletal supports of a set of 

 primitive oral cirrhi such as are found still in Amphioxus and in myxinoids. Others, 

 like Sewertzoff (1916), believe the labial cartilages to represent vestiges of the visceral 

 arches of two segments in front of the mandibular. Concerning this view Goodrich 

 (1930, p. 448) writes as follows: ''Against the theory maintained by Sewertzoff it may 

 be urged that there is no good evidence of the existence at any time of gill-pouches, 

 arches, etc., anterior to the mandibular, that the labials are too superficial to be of visceral 

 nature, and that the supposed vestiges of giU-pouches corresponding to them apparently 

 occur anteriorly to the pharynx (endodermal gut). Possibly the labials are merely 

 secondary in Gnathostomes and of no great morphological importance." The labials 

 may be tentatively classified as extravisceral cartilages of the mandibular arch, in series 

 with the extrahyoids and the extrabranchials. 



