DISCOGNATHUS. 181 



Twelve or thirteen species of Biscognatlms appear to be properly established — seven 

 or eight from North-east Africa * and five from Southern Asia, the range of distribution 

 of the genus in the latter part of the world extending from Syria and Arabia to the 

 Himalayas, Burma, and Southern China. The Asiatic species are much in need 

 of revision. 



Synopsis of the Species. 



I. Pupil of the eye in the second half of the length of the head ; barbels not more than half the 



diameter of the eye ; caudal peduncle once and one-third to once and a half as long as deep ; 

 scales in the lateral line 36 to 40. 

 Snout projecting strongly beyond the mouth, the width of 

 which is less than half the length of the head ; upper 

 lip well developed, with a series of papillae forming a 



fringe 1. D. dembeensis, Riipp. 



Snout projecting feebly beyond the mouth, the width of 

 which equals half the length of the head; upper lip 

 scarcely developed, not fringed 2. D. johnstonii, B]gr. 



II. Pupil of the eye in the middle, or anterior to the middle, of the length of the head ; barbels 



one-half to four-fifths the diameter of the eye ; upper lip well developed, fringed. 

 Mental disk well developed, with free posterior border formed 



by the lower lip ; caudal peduncle as long as deep ; 



35 to 38 scales in the lateral line 3. D. vinciguerrce, Blgr. 



Mental disk small, often very indistinct, or reduced to a mere 



pad, without or with a very slight free posterior border ; 



caudal peduncle about once and a half as long as deep ; 



37 to 42 scales in the lateral line 4. I). quadrimaculatus, Riipp. 



1. DISCOGNATHUS DEMBEENSIS. 

 (Plate XLVIII. fig. 1.) 



Chondrostoma dembeensis, Riippell, Mus. Senckenb. ii. p. 16, pi. ii. fig. 4 (1837). 

 Gymnostomus ? dembeensis, Heckel, Pussegger's Peise Egypt, iii. p. 329 (1846). 

 DiscognatJius dembeensis, Boulenger, Ann. & Mag. N. H. (7) xi. 1903, p. 54. 



Body feebly compressed, its depth four and two-thirds to six and a half times in the 

 total length. Head moderately depressed, once and one-fourth to once and a half as long 



* A key to the determination of the six species then known from Africa has been given by me in Proc. 

 Zool. Soc. 1903, ii. p. 331. Two species have since been added : D. hindii, Blgr., 1905, and D. rothschildi, 

 Pellegr., 1905, the former from the Kenya district, the latter from the Grota Eiver (Hawash system). 



