26 H. B. POLLARD. 



In all Siluroids, this prepalatine piece never enters into continuity 

 with the pterygoid cartilage, the latter being attached by ligament to 

 the vomer. The lateral velar supports which may, as in Callichthys 

 (Figs. 6 and 7) be of considerable size are apparently derivatives of 

 the maxillary tentacle. 



As to other Teleostei, Balfour remarks of the Salmon: " The anterior 

 bar of the upper arcade is known as the palatine ; but it appears to 

 me as yet uncertain how far it is to be regarded as an element 

 primitively belonging to the upper arcade of the mandibular arch 

 which has become secondarily independent in its development ; or as 

 an entirely distinct structure which has no counterpart in the Elasmo- 

 branch upper jaw. The latter view is adopted by Parker and Bridge, 

 and a cartilage attached to the hinder wall of the nasal capsule of 

 many Elasmobranchs is identified by them with the palatine rod of 

 Teleostei " (Prepal.). The development of this region in the Salmon 

 has been worked out by Stohr, who finds that tissue in the anterior 

 trabecular region gives rise to trabeculae, palatine cartilage (Prepalatine), 

 and tissue underlying the maxilla. The fusion of palatine and ptery- 

 goid elements occurs later. I have followed the process also in Gobius. 

 It might be considered that these ontogenetic stages recapitulate the 

 condition in Siluroids, but that can only be in a very limited sense, 

 inasmuch as the piece in Siluroids is moveable, with special muscles, 

 and does not bear any close resemblance at all to this embryonic con- 

 dition. Indeed the resemblance is really closer in the adults. 



In the Sturgeon free prepalatine cartilages exist, at any rate in the 

 young animal, outside the basal angle (Basalecke) in front of the 

 mouth. They may be the ethmo-palatines of Parker, but his lack of 

 precision reduces the value of his observations. I cannot tell what 

 Parker meant, since enthusiasm cannot replace accuracy. In Poly- 

 plerus there is a separate ossification (autopalatine, v. Wijhe), in the 

 upper jaw, where it articulates with the ectethmoid, -and the cartilage 

 projects forwards beyond this point. This is here called prepalatine. 

 A similar projection occurs in Chlamydoselachus (Gar man), so that, in 

 this form, we must conclude that the prepalatine is really included in 

 the jaw, in the region of the articulation with the preorbital process. 

 In Heptanchus and Hexanclius, a posterior portion of the pre-palatine 

 piece would appear to be represented by the "Lateral process of the 

 ethmoidal region M," of Gegenbaur, which the latter homologizes with 

 the " Schadelflossenknorpel " of Rays. 



