404 H- B- POLLARD, 



of the toDgue apparatus, the piece W oî Müller and my Mck (Fig. 11). 

 To the base of this tentacle, but not fusing with it, extends the pro- 

 cess from the cranium, which Müller termed the cartilaginous pro- 

 cess at the anterior end of the palatal ridges", the Processus spinosus 

 of FüuBRiNciER, or the Prepalatiue of Parker. 



The coronoid tentacle extends downwards and has an expanded 

 root piece of hard cartilage. The prepalatine piece is in continuity 

 with the ethmoid region, and thence with the subocular bar (Gaumen- 

 leiste of Müller), and the subocular bar is continuous with the 

 auditory capsule and basilar part of the skull. 



Müller makes the following remarks on the origin of the tirst 

 cranium. On the fibrous membrane of the chorda tube arise paired 

 cartilaginous rudiments of basilar pieces, running out into the audi- 

 tory capsules and forwards as lateral wings. This is shown in Animo- 

 coetes and Myxine. From this stage chondrification has proceeded 

 further, and ])y various steps the condition of the chondro-cranium of 

 higher vertebrates is attained. This is the simple view of Müller, 

 and to me it seems still the most correct. Indeed where the con- 

 ception of recapitulation in ontogeny has, in spite of the arguments 

 of V. Baer, Gegenbaur and others, been introduced, there has often 

 been great retrogression from the truth. Müller does not come to 

 any conclusion as to the origin of the subocular regions and of the 

 prepalatine piece. The prepalatine piece I regard as the root piece 

 of a tentacle, and since there is no break of continuity in the skull 

 of Myxinoids we may perhaps regard the subocular bar and "quadrate" 

 regions as outgrowths and extensions of fused vertebral and tentacular 

 elements. 



This would mean that the autostylic condition of suspension of 

 the jaws is the most primitive condition. To this conclusion I have 

 come in a recent paper from quite different grounds. 



The Labials (sensu stiictiori). 



Comparison of the traces of premaxillary, maxillary, and coronoid 

 tentacles brings us to the question of the lal)ials , as the term is 

 strictly used by Gegenbaur. I shall treat of the subject rather in 

 a historic way. 



CuviER (1814) dealt with the upper jaw of fish and came to the 

 conclusion that the maxillary bones (labiaux ou mystaces) and inter- 

 iiiaxillaries corresj)ond to the two labials of Squatina and other sharks, 

 while in the liays the intermaxillaries are represented by the small 



