464 PHYSOSTOMI. 



Alius Boalcei, Turner, Journ. Anat. and Pliy. 1866, i, p. 78'. 



? Arius falcarius, Giinther, Catal. v, p. 168, and Fisli. Zanz. p. 114. 



B. vi, D. i 1 0, P. 1/10, V. 6, A. 18-20 (yflf^), 0. 17. 



Length of head 4 to 6, of caudal 6, height of body 5|- to 6 in the total length, ^i/^s— diameters 

 5i- to 6 in the length of head, 2| diameters from the end of snout, and 3 to 3^ apart. The greatest width of 

 the head equals its length behind the angle of the mouth, and exceeds its height by about one-sixth. 

 Upper jaw the longer, the width of the gape of the mouth equals 3/7 of the length of ithe head. The median 

 longitudinal groove on the head, which is wide anteriorly, becomes suddenly narrow midway between the front 

 edge of the eye and the hind edge of the opercle, it does not quite reach the base of the occipital process, which 

 is keeled, rather longer than wide at its base, and reaches the basal bone of the dorsal fin which is V-shaped, 

 narrow, and short. Tipper surface of the head behind the eyes (except in groove) strongly granulated, as is 

 also the occipital process. Barbels — ^the maxillary pair, which are black, reach to the hind edge of the head, 

 the outer mandibular ones to the gill-opening, whilst the inner are shorter. Teeth — the villiform band 

 in the premaxiUaries four times as long as wide : those on the palate granular anteriorly, becoming globular 

 posteriorly, in two elongated semi-triangular patches, longer than wide, they are parallel to one another 

 along the median Kne, whilst their external edge is convex, anteriorly they nearly reach the premaxillary teeth. 

 Fins — dorsal higher than the body, its spine usually ending in a soft point, it equals the length of 

 the head excluding the snout, anteriorly it is serrated in its upper, rough in its lower half, it is serrated 

 posteriorly : the base of the adipose fin equals 3/7 of that of the rayed fin. Pectoral spine a little longer than 

 that of the dorsal, serrated externally in its outer half, rough along its lower, whilst iuternally it is denticulated, 

 it nearly reaches the ventral, whilst the latter extends to the anal or even to as far as the third ray. 

 Colours — ^bluish-gray superiorly, becoming dull white beneath : fins grayish, dorsal black tipped, a black blotch 

 on the adipose dorsal, and sometimes one on the anal. 



Habitat. — Calcutta, seas of India, to China. Very numerous along the Malabar coast. 



15. Arius Malabaricus, Plate CVII, fig. 4 (head). 



B. vi, D. f I 0, P. 1/10, V. 6, A. 20 (A), 0. 17. 



Length of head 4t, of caudal 6i, height of body 5 in the total length. .E72/e« — diameters 65 in the length 

 of head, 2| diameters from the end of snout, and 3J apart. The greatest width of the head equals its 

 length behind the nostrils, it is rather wider than high. Upper jaw the longer, the width of the gape of the 

 mouth equals 2/5 of the length of the head. Upper surface of the head sparingly granulated. The median 

 longitudinal groove on the head commences opposite the hind edge of the eyes, is very narrow and deep, and is 

 continued nearly to the base of the occipital process, which latter is slightly keeled and granulated, as broad at 

 its base as it is long and emarginate posteriorly to receive the V-shaped basal bone of the dorsal fin. 

 Barbels — the maxillary pair black, and, as long as the head, the outer mandibular ones rather shorter. Teeth — 

 in the upper jaw 1/4 as wide as long, those on the palate granular and in two elongated oval patches 

 which reach far forwards, are slightly convergent anteriorly, whilst they extend some distance posteriorly. 

 Fins — dorsal spine of moderate strength, as long as the head behind the angle of the mouth, anteriorly 

 granulated in its lower, serrated in its upper portion, posteriorly serrated : base of soft dorsal rather short. 

 Pectoral spine nearly as long as the head, denticulated internally, it extends to below the last dorsal ray. 

 Ventral does not quite reach the anal. Colours — silvery, glossed with gold inferiorly : adipose dorsal with a 

 black spot in its upper half. 



The upper surface of the head is entirely destitute of the ridges seen in A. gagora. 



Habitat. — Canara. 



16. Arius platystomus, Plate CVII, fig. 3. 



B. vi, D. i/0, P. 1/10, V. 6, A. 19 (^), C. 17. 



Length of head 4, of caudal 6i, height of body 5 in the total length. Eyes — diameters 7 in the length 

 of head, 2 diameters from end of snout and 4 apart. The greatest width of the head exceeds its height by 

 1/3, and is as long as the head without the snout. Upper jaw the longer, the width of the gape of the 

 mouth equals 4/7 of tbe length of the head. Median longitudinal groove on head becomes narrow posteriorly, 

 where it just reaches the base of the occipital process which is strongly keeled, rather longer than wide at 

 its base, with straight lateral edges, whilst it reaches the basal bone of the dorsal fin which is rather naiTOw 

 and S-shaped. A very few scattered granulations over the posterior half of the head and the occipital 

 process. Ba/rbels — the maxillary ones reach just beyond the base of the pectoral, the outer mandibular ones 

 are not quite so long. Teeth — the villiform band in the premaxiUaries, six times longer than wide : obtusely 

 conical in the palate in a pyriform patch, rather longer than broad, and which is placed weU forwards, it is 

 largest anteriorly where they slightly converge together, the interspace equals 2/3 of the diameter of the eye. 

 Fins — the dorsal about as high as the body, its spine as long as the head excluding the snout, anteriorly 

 its upper half is serrated superiorly, its lower roughened, it is serrated posteriorly : the length of the base 

 of the adipose dorsal nearly equals that of the rayed fin. Pectoral spine rather shorter than that of the 

 dorsal, externally serrated in its anterior, rough in its posterior half, internally it is denticulated, it reaches 

 3/4 of the distance to the ventral. Ventral just reaches the anal. Colours — bluish along the back, becoming 



