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Fig. 15. 



Aniphisile slriguta. IükIiI liyoid 

 .'lieh, from the outer side, si : 

 stylohynl; ch: eei;itühy;il ; cli: 

 .■pihy.-il; hy': Iciwer hy|i(iliy:Ll. 



this side, as its upper part is covered iiy the stylohyal; on the other liand, a great 

 deal of the ceratohyal (ch) is to be seen; along with the hypohyal I (hy I) it forms 

 the most of the hyoid arch to be seen from the outer side. When observed from 

 the inner side, however, the epihyal is of good size (fig. 16) and connected ante- 

 riorly with a small hypohyal II {hy II) and with hypohyal I; 

 posteriorly it covers the stylohyal, which is almost completely 

 hidden; of the ceratohyal only a small |)art is seen (ch). The 

 (in other fishes) upper hypohyal II (h^.II) is very small; as 

 in other bony fishes it is firmly attached 

 by a ligament to the basis of the glos- 

 sohyal. The lower hypohyal {hy I) is, 

 as already mentioned, the largest bone 

 in the whole arch , composing about 

 half of its length ; its front end is some- 

 what bent downwards (larger and stron- 

 ger in A. strigaia than in A. scutata); it 

 is connected for a long distance with 

 the corresponding bone of the opposite 



side, and a cartilaginous mass is found on the inner side of 

 the anterior end. Cartilage is also present between the epi- 

 and ceratohyal in the lower, thinner part of the posterior por- 

 tion of the arch, further in the interior of the bones. In a 

 depression on the outer side of the arch formed by the epi- 

 and ceratohyal (fig. 15**) and overhung by a projecting ridge are 

 attached the 4 branch iostegals (see fig. 14). The hindmost (up- 

 permost) of these is the strongest and largest, the first quite thin 

 and short. A groove under the base of the curved front end 

 of the hypohyal I is for the attachment of the strong ligament 

 for the urohyal. This bone (PI. II, fig. 1 ii) is of a considerable 

 size and is continued backwards in 2 

 very long, thin bones, each of which 

 runs far back on the outer aspect of the 

 clavicle of its own side and serves as 

 tendon for the attachment of a feather- 

 like muscle; the posterior portion of this 

 muscle is attached to the postclavicle 



Fig. 17. 

 Amphisile sciilatu Ciill- 

 arches seen ironi a])ove ; 

 on the right side the hyoid 

 and upper parts of the 

 arches have been remo- 

 ved, gl : glossoliyal ; liyo : 

 left liyoid; fo'- co'": co- 

 pulie(!)asibraneliials); hy: 

 Itypobraneliials ; c : cera- 



tobraneliials 



«'-e": 



branehials; ph'—jih 

 pharyngobrancliialf 



ej)!- 



{pel), whilst the libres arising ventrally A-sniyuiu. uigiit hy 



^ .1,3 i- 1 1 .1 inner side. Letters; 



Irom the tendon are lixed along the 



n fig. 

 y»;": upper hypohyal. 



outer side of the coracoid (oo). 

 The glossohyal (enloglossal, lingual; fig. 17, gl)is very long, fiat and thin; in 

 A. scutata it is of the same length as the whole of the remaining portion of the 

 gill-arches, in A. strigata even somewhat longer. Seen from above it is leaf-like. 



