93 



Air-bladder present. Pyloric appendages small, almost rudimentary. 



The tail is so extremely slender and filiform that the end of it is often lost, 

 and when the caudal fin grows again it appears to be free from the other vertical 

 fins. 



The lash-like tail, the frilled crests of the head bones, and the compara- 

 tively large pseudobranchia? distinguish Glyptophidium. In no other Indian 

 Ophidioid do the pseudobranchise consist of more than 2 small filaments. 



Key to the species of Glyptophidium. 



I. Each ventral consists of a single filament ... ... ... 0. argenteum. 



II. Each ventral consists of two filaments ... ... ... G. macropus. 



72. Glyptophidium argenteum, Alcock. 



Glyptophidium argenteum, Alcock, Ann. Mag. Nat. Hist., Nov. 1889, p. 390 : Illustrations of the Zoology 

 of the Investigator, Fishes, pl. II. fig. 3. 



Length of the head about a fifth the total, greatest body height (at the 

 shoulder) equal to the length of the head without the snout. The body rapidly 

 tapers to a long filamentous tail. 



Length of the snout equal to the major diameter of the eye (which is nearly 

 a fourth the length of the head), barely equal to the width of the interorbital 

 space. 



The upper jaw overlaps the lower, except at the tip, where a sharp knob at 

 the mandibular symphysis projects slightly : its length is half that of the head. 

 Villiform teeth in a broadisb band on the upper jaw, in a narrow band on the 

 lower jaw, in a slightly curved narrowly-elliptical band on the palatines, and 

 in a A-shaped band on the vomer. 



Three weak points at the angle of the preoperculum. Numerous long 

 gill-rakers on the outer side of the 1st branchial arch. Each pseudobranch 

 consists of about a dozen filaments. 



Scales rather large, excessively thin and deciduous, — more especially on the 

 head, so that in specimens that are not exceptionally well preserved the head 

 appears naked. 



Dorsal and anal fins confluent with the caudal, the rays of the anal being 

 much shorter than those of the dorsal and the rays of all three being very 

 slender : the longest dorsal rays are nearly half the body height. 



Pectorals pointed, a little longer than the head without the snout, the rays 

 very slender and about 22 in number. 



Each ventral consists of a single slender ray which is about as long as the 

 post-orbital portion of the head. 



