2 2 Account of Observed Fotius of Laryivc. 



ascribed to Chasmarhynchis nudicollis, by whicb name I shall benceforward designate 

 tbem. 



Chasmarhynclms canmcnlaUis. The whole larynx is surrounded, on all sides, by a 

 thick layer of muscle, which forms, with the larynx lying beneath, two large balls, 

 united together. Moreover, on the lower surface of the jiessulvs lies muscle, which 

 covers the greater jiart of it. But the enormous mass of muscle, which is provided 

 with a very thick nerve (a branch of the var/us), is not divided into separate muscles, 

 as in the so-called muscular organ of voice, but nearly all the bundles of muscle 

 form a united inseparable whole, of which only a right and left moiety are distin- 

 guishable, perfectly close to each other anteriorly, as well as posteriorly. All the 

 fibres, anteriorly, laterally, and posteriorly, have a similar course from above downwards. 

 Very peculiar and unexampled is, also, the fact that a great, and indeed the greatest 

 portion, of the muscle is not arranged for the movement of the bronchial rings, but is 

 inserted, between the lower edge of the larynx and the first half-ring, into the mucous 

 membrane, while the muscular fibres, rising in the form of a bow, are set with their 

 ends jjerpendicular to the mucous membrane. Thus there is formed a thick cushion-like 

 muscular labium, on the outer wall of the organ of voice, at the entrance of each 

 bronchus. See the section, Plate I, Fig. 7. The cushion-like labium has, on its inner 

 aspect, opposite the cavity of the organ of voice, two surfaces, an upper larger and 

 a lower smaller, which turn towards the first half- ring ; on the edge, where the two 

 surfaces meet, there lies an elastic strap, the outer vocal band. The muscular mass of 

 the labium forms the thick deeper portion of the muscular covering. The superficial part of 

 the covering, which is in no way separated from the deeper part, causes all the bundles 

 of muscle, which come to the labium, to be invisible, and is used for the movement of 

 the first and second half-rings. The first half-ring is enwrapped by it in its whole 

 breadth, the second only at its anterior and posterior ends. The second half-ring can 

 be slightly separated from the first, which is completely hidden in the muscle : between 

 the second and third there» is a large semilunar interspace; and the following half-rings 

 arc ao-ain nearer to one another. On the anterior face, the muscle curves across the lower 

 edge of the larynx, so as to embrace the anterior ends of the first two half-rings ; on 

 the posterior, the muscle passes over the lower edge of the larynx to go to the memhrana 

 tpnjjaniformis of each bronchus, which is held in tension at the point where it is 

 fastened to the lower edge of the larynx, or of the pessulus, by a short broad muscle — 

 a continuation of the course just described. 



The outer end of this continuation of muscles projects sharply forward into the 

 membrana iympaniformis, and breaks up into elastic bundles, which lie in this thick 



