308 H. H. WILDER, 



this muscle attaches to the inner edges of the two thyroid processes, 

 which thus serve the new muscle as points of origin. 



The muscle also loses its connection medially with the rest of 

 the ring, retaining however a bit of the raphe in the form of a 

 median tendon, loosely attached to the edges of the underlying ary- 

 taenoid cartilages. In Äcris and ChoropJiilus this connection is never 

 lost, but the two muscles remain continuous in the adult state (Figs. 

 51 and 54). In Rana temporaria, the cartilages of which do not 

 effect the usual rotation, this muscle retains its larval position, but 

 in the other species of this genus it descends with the apex of the 

 cartilage and stretches across the anterior third of the pharyngeal 

 side (Fig. 31). 



This muscle is called by Henle the "Verengerer des Aditus 

 laryngis", which name it will be well to partially retain as Con- 

 strictor laryngis (es), bearing in mind its origin from the 

 muscular ring. 



Soon after the "Anlage" of this muscle has appeared about the 

 ventral raphe, a new moment is introduced by the gradual growth of 

 the annulus and the formation of the anterior cardiac processes. 

 These, pressing upon the ring-muscle from beneath, separate its lower 

 fibres in the same manner by which the secondary slips of the Dila- 

 tator become separated. These divide the deeper portion of the ring 

 into the four quadrants shown in Fig. 34, and called by Göppert 

 the Sphincter posterior. The more superficial fibres do not be- 

 come thus involved and form on the pharyngeal (dorsal) half of the 

 ring a pair of band-like muscles , which secondarily attach to the 

 thyroid processes of the hyoid. These form the Sphincter anterior 

 of Göppert and the Compressor laryngis of Henle (Figs. 32 

 and 33). They are the counterpart of the Constrictor aditus 

 laryngis of the ventral side, the latter being derived from the 

 ventral half-ring (Peri-arytaenoideus ventralis of my former paper) 

 and the other from the dorsal half-ring (== Peri-arytaenoideus dor- 

 salis). In the majority of forms, the anterior pharyngeal processes 

 do not protrude far enough to involve any portion of the ring, which 

 then develops entirely into the Constrictor dorsally and the 

 Compressor ventrally (Bufo, Fig. 42). 



b) Nomenclature of laryngeal muscles. 

 It is a well-nigh impossible task to select names, either from the 

 many already proposed, or by framing new ones, which are capable 



