Account of Observed Forms of Larynx. 



membrane. The memlrana tpn^Mniformis has, further, an anterior tensor, which lies 

 on the anterior half of the pessulus, in the lower median part of the larynx, and 

 consists of cross bundles. They do not arise from the pessulus, but are united to it by 

 a median tendinous strap. This cross muscle is, similarly, a continuation of the mus- 

 cular layer of the anterior face of the larynx. In Chasmarliynclms muVicoUis it is, in 

 fact, a direct continuation of it, but in this species it appears as a separate muscle. 



The musculus sternotrachealis arises more from the anterior than from the lateral 

 faces, just above the covering of muscle. 



CJiasmarJipicJms nucUcoUis. The organ of voice is, broadly speaking, formed in just 

 the same way, the muscular labium is again present, and the whole arrangement of 

 the muscular supply is on the same plan; nowhere can any separation into distinct 

 muscles be recognised. The superficial layer of the thick muscular mass, so far as can 

 be seen, laterally, ends in the first and second half- rings of the bronchi. The first 

 rin"- is quite enveloped in muscle, the second is supplied by the external muscular bundles 

 anteriorly and posteriorly, which are inserted not only into its ends, but, also, somewhat 

 into its whole extent. On the anterior and posterior faces of the larynx, the bundles 

 of muscle go to the inferior surface of the organ, between the bronchi. Those of the 

 posterior face embrace a cartilaginous projection of the bone of the larynx, to which 

 the first half-ring, as also the end of the first and second half-rings, is fastened. But 

 the muscle passes forward to the pessulus; this portion of the muscle which stretches 

 the inner vocal band, arises as much from the anterior median portion of the larynx, 

 as from the pessulus. C. ntulicolUs has, it must be said, a very thick inner vocal band, 

 of which there is no trace in C. caruncwlatus. This band is fastened to the hinder edge 

 of the bone of the larynx, and superiorly it passes on to the just mentioned tensor muscle. 

 The muscular bundles wind round this band, just like a string grasped by the 

 fingers and the hand, and must produce a considerable tension of the elastic band. This 

 muscle extends over half the length of the pessulus. In a vertical section of the lateral 

 masses of the muscle of the larynx, one recognises at once the muscular outer labium, 

 and the fine external vocal band lying on it. Here also the considerable space, between the 

 lower edge of the larynx and the first half-ring, is occupied by a thick layer of muscle, 

 taking its origin from the larynx, and rendered invisible by the superficial layer which 

 belongs to the half-rings ; it is directed in a curve towards the mucous membrane. In 

 this muscular wall, where the mucous membrane receives the ends of the muscular 

 fibres, a larger inner, and a smaller lower, layer, are distinguishable, to the edge of which 

 the elastic strap, or external vocal band is directed. 



