328 AOHONURID-f. 



panic especially is well developed, occupying the whole of the ante- 

 rior side of the prfeoperculum. The prseorbital is very elongate ; the 

 other bones of the infraorbital ring are firmly united together, and 

 the posterior ones are in immediate contact with the inner ridge of 

 the pra^operculum, as in Chcntodon. The angle formed by the limbs 

 of the prsRopercuIum is veiy obtuse ; the lower limb has only half 

 the length of the posterior : operculum rather narrow and elevated, 

 not extending downwards to the angle of the prseoperculum, where 

 it is replaced by the suboperculum : interoperculum small. 



The bones of the humeral arch are rather strong : the suprascapuia 

 is fii-mly united with the skull ; scapula long, broader in its inferior 

 half than in its superior ; coracoid very long and strong, straight. 

 The cavity for the pectoral muscles, which is formed b}^ the humerus 

 and the bones of the fore-arm, is very broad and rather deep ; its 

 bottom is nearly entirely osseous, the ulna having a small foramen, 

 the radius a larger and a smaller one. The pubic bones are very 

 long, slightly bent, and firmly attached to each other, leaving scarcely 

 any free space between them. 



There are nine abdominal and thirteen caudal vertebrce, the length 

 of the former portion of the vertebral column being to that of the 

 caudal as 1 : l'G6. The vertebrae are somewhat elongate, not com- 

 pressed. All the apophyses are strong, and those of the anterior 

 caudal vertebrae rather long. The nem'als and interneurals of the 

 abdominal vertebrae are so dilated into lamellae posteriorly, that the 

 whole forms one continuous osseous plane, without free spaces be- 

 tween the single bones. The first interneural is exceedingly strong 

 and compressed ; it is dilated superiorly, the dilated portion ending 

 in a spine anteriorly, behind which is a deep incisure to receive the 

 base of the first dorsal spine. The second interneural is firmly 

 attached to the first. The interneurals of the following dorsal spines 

 are dilated superiorly into a slightly concave plate, as in TenfJils, and 

 one always corresponds to a single neural, whilst each neural and 

 haemal of the caudal vertebrae alwajs support two interneurals and 

 intcrhaemals of the soft rays. The first interhacmal is similar in 

 structure to the first interneui'al, but much longer, and its dilated 

 portion has no spine anteriorly. Ribs well, developed, with epi- 

 pleurals. 



lines. 

 Length of tlie first vertebra 01- 



of the second vertebi'a 1 j 



'I 



of the third vertebra 1\ 



— of the fourth vertebra . 2-^ 



of the tenth vertebra 2| 



of the twentieth vertebra 2 



of the abdominal portion 19 



of the caudal portion 31 ^ 



of the eleventh neural spine 11 



— of the first htcmal spine 14 



— of the first interneural spine 7 



— of the first intcihacmal spine 19 



