The Amphibian larynx 285 



3. Salaniandridae, 



The condition of the respiratory cartilages in this group is 

 essentially that of the preceding, but the varying length of the trachea 

 exerts a modifying influence upon the tracheal elements. In Triton 

 (Figs. 27 and 28) where the reduction of the trachea is as great as 

 in the Anura, the tracheal pieces are broad and applied to the curved 

 portion representing the bronchial region. Their irregular contour, 

 with the characteristic projecting points (Henle's incipient tracheal 

 rings) still show similarity to their form in the previous group. 

 Fig. 25, drawn from a methyl-blue preparation of the allied genus 

 Salamandra, exhibits also the usual irregularity and fragmentary 

 nature of the pieces composing these elements. Amhlystoma (Fig. 26) 

 shows the form of these pieces in a species with long trachea. 



It is also important to note the changes in the form of the ary- 

 taenoids (Fig. 29, Triton)^ which show a tendency to become concave 

 upon their inner surfaces. The external lateral projection for the at- 

 tachment of muscles is well-marked (cf. Siren, No. 11, plates). 



The group of lungless Salamandrids should receive men- 

 tion here. Of these, six species have already been enumerated, two 

 by Camerano (No. 1) and four by myself (No. 13). As they have 

 not all been subjected to the section method, it is quite likely that 

 some may exhibit traces of the respiratory cartilages. In the case of 

 DesmognatJius and Plethodon I have cut serially several larval stages, 

 as well as the adult, in all cases with negative results. 



4. All/ tes obstetricans. 



The modifications undergone by the Anuran laryngeal cartilages 

 are considerable, and in most of these the Urodelan type is scarcely 

 to be recognized. The main modifying influence here is the excessive 

 reduction of the trachea and the consequent breadth in that region. 

 For the purpose of keeping this broad passage dilated, the tracheal 

 elements unite more or less completely into the form of a ring which 

 has been called the "cricoid" by the older authors. This name is 

 plainly mislending for in this complex there are included not only the 

 elements which form the cricoid of higher types, but also all the 

 other tracheal and bronchial elements. This confusion may be ob- 

 viated by the non-committal name of A n n u 1 u s , which suggests its 

 form without implying erroneous homologies. The secondary out- 

 growths from the hyoid complex, the Processus thyreoidei or 



