•FAMILY, I— SILUEID^. 457 



in their moutLs. Some of these eggs were ia an early stage of development, others nearly ready to be hatched : 

 whUst in the mouth of one specimen was a hatched fry having the yolk bag still adherent. The eggs filled the 

 cavity of the mouth and extended far back to the branchiae. 



In the female organs of generation the eggs seemed to come to maturity in batches of perhaps 60 at 

 a time. On examining the conformation of the ventral fins, those of the females appeared to be larger than 

 those of the males : the rays were thickened by a deposit of fat, whilst the innermost one had a large similar 

 pad attached to its posterior edge. These fins can be expanded into a cup-like surface, the use of which may 

 be to receive the eggs as extruded, which may be vivified there by the male. 



Whether the male carries about these eggs in his mouth until hatched or only removes them when 

 danger is imminent from some spot where he is guarding them is questionable, but in none of the specimens 

 which I examined did I find a trace of food in the intestines of the males which had been engaged in this 

 interesting occupation. 



This has been observed likewise elsewhere by Mr. Boake in Ceylon, and Dr. Hensel has recorded the 

 same of a Brazil species A. Gommersonii : Dr. Giinther of Arius fissus from Cayenne : and the same facts have 

 been remarked in other Siluroid fishes. 



Geographical distribution, — Seas and estuaries of tropical regions, ascending to within the tidal influence 

 or even entering fresh waters. They appear to be almost as unknown in the Red Sea as the ScicenidcB, and 

 probably due to the same cause (see p. 181). 



Uses. — As food of an inferior quality. On the "Western coast of India they are largely salted and 

 a considerable amount of coarse isinglass is procured for export to China by drying their air-vessels. 



SYNOPSIS OP SPECIES, 



A. Villiform teeth on the folate. 



1. Arius Burmanims, A. 19-22. Head 3| to 3| in the total. Eye, 7 to 8| in length of head. Mouth 

 spatulate. One patch of teeth not as large as eye on either side of palate. Burma. 



2. Arius nenga, A. 19. Head 4J in total length. Eye, 6 in length of head. Maxillary barbels reach 

 last third of pectoral fin. Two triangular patches of teeth approximating superiorly. Dorsal spine as long as 

 head. Dull yellow, fins blackish. Hooghly at Calcutta. 



3. Arius ccelatus, A. 19. Head 4i to 4f in the total. Eye, 6 to 9 in the length of head. MaxiUary 

 barbels reach middle of pectoral fin. Two somewhat triangular patches of teeth, approximating anteriorly. 

 Dorsal spine about as long as head. Seas of India to the Malay Archipelago. 



4. Arius acutirostris, A. 19. Head 3|- in the total. Eye, 7 in the length of head. Snout much produced. 

 Maxillary barbels reach hind edge of eye, Teeth in two obliquely ovate diverging patches. Dorsal spine half 

 as long as head. Salwein river at Moulmein. 



6. Arius Sumatranus, A. 18-19. Head 4J to 4^. Eye, 5 in the length of head. MaxiUary barbels reach 

 end of head. Palatine teeth in two triangular patches diverging posteriorly. Dorsal spine not so long as head. 

 Seas of India to the Malay Archipelago. -,r ■ i 



6. Arius venosus, A. 18-19. Head 6i in the total. Eye, 4^ in the length of head. Maxillary barbels 

 reach base of pectoral fin. Teeth on the palate in patches as large as the eye, of a triangular shape, as broad as 

 long, and directed backwards. Dorsal spine as long as the h^ad behind the angle of the mouth. Nicobars, &c. 



7. Arius piwvipimnis, A. 19. Head 4| in the total length. Eye, 5| in the length of head. Maxillary 

 barbels reach the end of the pectoral fin. Palatine teeth in a pear-shaped patch, the small end forwards and 

 converging, widely diverging posteriorly. Dorsal spine nearly as long as the head. Coromandel coast of 



' 8. Arius suhrostratus, A. 17-20. Head 3i to 4 in the total. Eye, 6 to 6:in the length of head, and 2i 

 to 3 diameters from end of snout. Maxillary barbels do not quite reach the eye. Teeth on the palate ma 

 patch on either side not longer than the eye, and wide asunder. Dorsal spme rather above halt as long as head. 



9. Arius sagor, A. 17-19. Head 4^ to 4^ in the total. Eye, 6i to 7 in the length of head. Head very 

 broad : basal bone of dorsal fin large and butterfly-shaped. Maxillary barbels reach middle or end of pectoral 

 spine. Teeth in two confluent patches on either side meeting anteriorly. Dorsal spme as long as the head 

 excluding the snout. Seas and estuaries of India to the Malay Archipelago. , ^ , ^ ,, .,, , , , 



10. Arius sona, A. 17. Head 4 in the total. Bye, 7 to 9 in the length of head. MaxiUary barbels 

 reach the end of the head. Palatine teeth on either side in a large triangular patch, emargmate posteriorly, 

 and 'anteriorly conjoined by a smaU vomerine patch. Dorsal spine as long as the head excludmg the snout. 

 Seas and estuaries of India and Burma. ., . ,, , . i, j? j.-u i,„„;i -M-„^.:n„-„ 



11. Arius serratus, A. 16. Head 5| in the total length. Eye, 4J m the length of the head. MaxiUary 

 barbels reach the middle of the pectoral fin. Teeth on the vomer and palatines m three patches on either side 

 converging in the median line anteriorly. Dorsal spme as long as the head behmd the middle of the 



^^''" 12!^Ariusthalassir.us,A.l5-17. Head 4^ to 6 in the total length. Eye, diameter 6 in the len^h of 

 the head. Maxillary barbek reach base of pectoral fin. Teeth on vomer and palatmes m three patches on 

 either side joining anteriorly in the median Une. Dorsal spme nearly or quite as long as the head. Red Sea, 

 seas of India to the Malay Archipelago and beyond. ^ ^ 



