PHYSAILIA. 321 



6. PHYSAILIA. 



Boulenger, Ann. & Mag. N. H. (7) viii. 1901, p. 445. 



Body elongate, very strongly compressed, the praecaudal region very short ; no rayed 

 dorsal fin, a very small adipose ; anal fin much elongate, extending from the ventrals 

 to the caudal. Pectoral fin with a spinous ray. Ventral fin small, with 6 rays. A 

 narrow band of very small teeth in the jaws, none on the palate. Eye large, with free 

 border, on a level with the mouth. Nostrils close together. Four pairs of barbels : 

 nasal, maxillary, and two mandibulars. Gill-membranes free, deeply notched. Air- 

 bladder small and free. 



This genus, represented by three African species *, is closely related to the Asiatic 

 Ailia, Gray, and the African Par ailia, Blgr., differing from the first in the free air- 

 bladder and the absence of vomerine teeth, from the second in the presence of a small 

 adipose dorsal fin. 



The skeleton is very similar to that of Eutropius, but the occipital process is short, 

 the vertebrae number 52, 11 praecaudal and 41 caudal, and there are 8 branchiostegal 

 rays. 



1. PHYSAILIA PELLUCIDA. 



Boulenger, I. c. 



Depth of body four to four and a half times in the total length, length of head six to 

 six and a half times. Snout broad, rounded, not projecting beyond the mouth, a little 

 longer than the eye, which is perfectly lateral and contained about three times in the 

 length of the head, and once and one-fourth in the interocular width ; latter a little 

 greater than the width of the mouth. Nasal and maxillary barbels two-sevenths to one- 

 third of the total length, reaching the extremity of the pectoral fin or a little beyond ; 

 mandibular barbels close together on the chin, subequal in length, one-third to two-fifths 

 of the total length. Gill-rakers long and slender, about 30 on lower part of anterior 

 arch. Pectoral fin obtusely pointed, as long as the head, extending beyond the root 

 of the ventrals, the spine a little shorter and serrated on the inner side. Ventral fins 

 about one-third the length of the pectorals, about twice and a half as distant from the 

 caudal fin as from the end of the snout. Anal fin with 65 to 74 rays, the longest 



* Ailia somalensis, Yinciguerra, from the Ganana in Somaliland, and Ailia occidentalis, Pellegrin, from Cape 

 Lopez, no doubt belong to this genus. 



2t 



