26 



by the same kind of deeply indented suture as that which unites the bodies of the occipital and 

 parietal vertebrae in this and other fishes. 



The posterior articular surface of the third trunk-vertebra is as remarkable for its shallow- 

 ness and breadth as the anterior one for its narrowness and depth. The parapophyses of this 

 vertebra are of great length, are depressed, flattened and extended outwards, and suturally 

 united by the whole of their anterior margin with those of the second vertebra. The neur- 

 apophyses are distinct from one another ; each sends off a zygapophysis, looking upwards from 

 the back part of its base, and terminates above in a short thick triangular spine, which arti- 

 culates anteriorly with the neurapophyses of the second vertebra. The centrum of the 

 second vertebra is twice the length of the third, and is irregularly excavated laterally, as well 

 as before and behind. The parapophysis is enormously developed in length and breadth, and 

 its anterior margin is bent upon itself, so as to circumscribe a deep canal leading outwards. 

 It extends outwards and upwards, and articulates not only with the parapophysis of the atlas, 

 but with the extremity of that of the occipital vertebra. 



The neurapophyses each send upwards a separate spinous process, which rise parallel with 

 each other, but are united together above the neural canal ; and their interspace receives the 

 hind margin of an enormous compressed neural spine, the base of which extends along the 

 neural arch of the atlas, and the anterior border of which articulates with the posterior border 

 of the spine of the occiput. 



Purchased. 



77. The dried skin of a Siluroid fish (Arius crutiger), showing the large denno- 



placoid plates of the exo-skeleton, and the proportions and position of the 

 strong pectoral and dorsal spines. 



The broad patches of tessellated small hemispheric teeth upon the palatines are worthy of 

 notice ; and the transverse group of short setiform teeth upon the premaxillaries. In the 

 lower jaw the setiform denticles are gradually transformed into the hemispheric tubercles, as 

 they are situated further back in the mouth. The cranial ganoid plate is cruciform, with a 

 granular surface, the granules running together into striae at the middle of the plate ; the 

 short arms of the cross touch, but are not confluent with, the scapular plates. The humeral 

 plates extend almost as far back as the strong pectoral spine which they assist in supporting, 

 and are rounded at their extremities as in the Anus rita. The dorsal plate is formed by four 

 bones ; its pointed anterior end penetrates a notch in the contiguous end of the cranial one. 

 The first short and strong dorsal spine overlaps the base of the second enormous one which 

 constitutes the chief weapon of defence of this Siluroid fish. The anterior border of this 

 spine has a fine ridge lodged in a slight longitudinal groove : some small teeth are developed 

 from the posterior margin, which is attached to the dorsal fin. This species of Arius is from 

 the Ganges ; the native name is ' Bilgugra.' 



Purchased. 



78. The interneural and dermoneural spines, forming the first ray of the dorsal fin 



of a large Siluroid. The summit of the interneural spine expands into a broad 



