470 PHYSOSTOMI. 



distance apart, both patent, the anterior situated in front of, or on the upper edge of the snout. Four slender barbels, 

 one maxillary and a pair behind the chin. Teeth villiform intermixed with conical ones in the jaivs : those in the 

 vomer, if present, distinct from those on the palatines. Dorsal fin inserted anterior to ventral and with one spine and 

 seven rays : adipose fin short. Ventral with six rays. Pectoral with a spine. Anal rather elongate (29 to 39 rays), 

 not confluent with the caudal. Air-vessel in the abdominal cavity and not enclosed in bone. One or more axillary 

 pores. 



This genus is divided by Bleeker in the following manner : — 



A. — Anterior nostril piatent and entirely anterior on the snout. 



1. Pangasius. Four groups of teeth ou the palate, those on the palatines close to the vomerine ones and 

 forming a transverse band. 



2. Pseudopangasius. Vomerine teeth forming a broad square patch, those on the palate in an oblong 

 lateral patch. 



B. — Anterior nostril patent on upper edge of the snout. 



3. Helicophagus. Teeth on the vomer if present in two small patches. 



Geographical distribution. — Large rivers and estuaries of India and Burma to the Malay Archipelago. 



SYNOPSIS OF INDIVIDUAL SPECIES. 



1. Pangasius Buchanani, D. -f/O, A. 31-34. Large rivers of India and perhaps Java. 



1. Pangasius Buchanani, Plate CVIII, fig. 5. 



Pimelodus pangasius, Ham. Buch. Fish Ganges, pp. 1G3, 378, pi. 38, f 52. 



Pangasius Buchanani, Cuv. and Val. sv, p. 4.j, pi. 425 ; Bleeker, Hind. pp. 68 and 118; Blyth, Proc. 

 A. S. of Beng. 1858, p. 286 ; Giinther, Catal. v, p. 62. 



?Pangasin,s djambal, Bleeker, Batav. p. 181, and Atl. Ich. SHur. p. 73, t. 1(> ; Giinther, Catal. v, p. 62. 

 Jellum, Ooriah. 



B. ix-x, D I/O, P. 1/12, V. 6, A. 31-34 (^:f^), C. 19. 



Length of head 5i to 6, of caudal 5 to 5j, height of body 4 to 5 in the total length. E yes —jtartlj on 

 the lower surface of the head, and in the commencement of its anterior half, the width of the interorbital space 

 equalling the length of the head excluding the snout. The greatest width of the head equals its length behind 

 the angle of the mouth. Upper jaw the longer : width of the gape of the mouth equals 3/7 of the length of 

 the head, its cleft reaches to below the hind nostril and is opposite the centre of the front edge of the eye. 

 Upper surface of the head smooth in small specimens, rather lincated in large ones especially along the occipital 

 process which is from 2i to 3 times as long as wide at its base. Barbels — the maxillary ones reach the base of 

 the pectoral fin : the mandibular ones are half as long as the head. Teeth — on the palate in a crescentic row, 

 the vomerine patches being either distinct from or just confluent with those on the palate. Fins — dorsal spine 

 of moderate strength, as long as the head behind the angle of the mouth, slightly serrated anteriorly, in its 

 entire length pesteriorly. Pectoral spine rather stronger than that of the dorsal, in some specimens of the 

 same length, in others as long as the head, denticulated internally. Caudal deeply forked. t'oZoMW— silvery, 

 darkest along the back and glossed with purple on the sides : cheeks and under surface of the head shot with 

 gold. Air-vessel — large, its anterior portion occupies about 1/2 the length of the abdominal cavity, and is then 

 divided by a constriction from the second portion, which is narrowed and divides into two small continuations 

 one of which extends on either side amongst the muscles covering the hteuial spines, as far as to above the 

 middle of the anal fin. The anterior portion of the air-vessel has a large pp-amidal and cellular cavity, the base 

 of which is anterior, on either side of this cellular cavity is a pyriform smooth chamber the two communicating 

 anteriorly. The remainder of the air-vessel is cellular or rather furnished with vahiilar-formed folds. 



Habitat. — Large rivers and estuaries of India, Assam, Burma, and perhaps the Malay Archipelago. It 

 attains upwards of 4 feet in length, and is a foul feeder. 



Genus, 10 — PsEUDECTEOPiUS,* Bleeker. 



Clupiisoma, Swainson ; Schilheicldhys, Bleeker. 



Branchiostegals from, six to ten. Gill-opienings wide, the membranes not confluent with the shin of the isthmus 

 and rather deeply notched. Body elongated and compressed. Head covered with soft skin. Eyes large, with or 

 vnthout broad adipose lids, and situated behind as well as a little below the angle of the mouth, being usually partly 



* Genns Eutropius, Mnller and Troschel, is clo.sely allied but has its mandibular barbels of each side placed one behind the 

 other: Dr. Guntber gives as its geographical distribution "Tropical Africa. Kast Indies." Two of the species he cites belong to 

 Psettdeutrnivus, the remaining one he describes as new. Eutropius ohtusirostris, Gunther Catal. v, p. 53, it seems to be of doubtful East 

 Indian origin : it was purchased in Liverpool, and is as follows; — 



}). i I 0,P. 1/8, V. 6, A. 54. 



Height of body 4i in the total length without the caudal fin : length of head 4|. Eyes without Jidipose lids. Maxillary 

 barbels as long as the head. Dorsal spine 3/4 as long as the head. Vomerine teeth in an uninterrupted transverse baud, not confluent 

 with the palatine one. India 3 inches long. This fish apjiears to me to be probably of African origiu. * 



