The Amphibian larynx. 295 



ventral portion ; the S'^^ is typical and possesses both; the 4tii arch 

 (i. e. the tendinous inscrii)tion) is also complete, and for the b^^ arch 

 (the arytaenoids), there is a large dorsal portion. Whether there 

 may be here anything corresponding to a ventral portion, will be dis- 

 cussed later. With regard to the current nomenclature of these 

 muscles, the three anterior dorsal portions are the Levatores ar- 

 c u u m 1 1 — I V, Levator arcus I failing in Necturus. The re- 

 maining dorsal portion was called by Henle (No. 9) the Dorso- 

 trachealis. The separate ventral portions of the muscular sheet 

 have been generally confused under the name of Hyo-trachealis 

 (Henle, Göppert), even this recent investigator (No. 6) overlooking 

 the important fact of separate insertions into two branchial arches. 

 If one recall a diagrammatic figure of mine published in 1893 (No. 12), 

 the almost complete correspondence between it and the actual con- 

 dition in Necturus will be seen. The musculature of the visceral 

 skeleton may be resolved into a series of sheet-like expansions, one 

 from each gill arch, and divided by the arch into a dorsal and ven- 

 tral portion. 



The accompanying diagram (Fig. A) is based upon Necturus, but 

 so completely corresponds to my former diagram that it may be sub- 

 stituted for it. The parts drawn in full are actually present in Nec- 

 turus, although the 4''' epibranchial is rudimentary. The 1^* Levator 

 arcus is so generally present in Urodeles that I have represented 

 its right to be included in this scheme, by a light shading. The only 

 portions not occurring in urodeles as far as they have been examined, 

 are the S^J and 4th ventral portions (belonging to the 1«' and 2"d 

 branchial arches) and these are left white in the diagram. Whether 

 these are represented ontogenetically, the much-needed embryology of 

 the Proteidae will decide. 



As the actual conditions in the primitive Urodeles so completely 

 coincide with the diagram, it may serve as a basis for a simple and 

 convenient terminology, and one of fundamental morphological value. 

 The dorsal and ventral series may be designated by the prefixes 

 dor so- and pharyngo-, to suggest the origins, and the terms may 

 be completed by the addition of the name of the visceral arch into 

 which they are severally inserted. 



This will give us the following set: 

 Dorso-mandibularis (D,) Pbaryngo-mandibularis (V^) 



Dorso-hyoideus (i^g) Pharyngo-hyoideus (V^) 



Dorso-branchialis 1 — biD^.-j) Pharyngo-branchialis 1— 5(Fg.7) 



