163 



prolonged into a long beak, which has no teeth, except In 

 the part opposite to the intermaxiliaries. This beak is bordered 

 by 3 more or less conspicuous folds of the skin, one along 

 each edge and a median one, beginning on the chin, Inter- 

 maxiliaries forming a triangular plate, which has a band of 

 teeth, similar to that of the lower jaw. The teeth are small 

 and conical. Origin of dorsal far backwards, somewhat before 

 that of anal, which is much shorter than the well developed 

 dorsal. In males some of the dorsal rays are often prolonged 

 and some of the anal rays much enlarged. The articulations 

 of lastnamed have increased in number and are much broadened. 

 From their posterior side a great number of very fine secun- 

 dary rays take origin, giving to the whole ray the appearance 

 of a bird's feather from which one half of the vexillum has 

 been removed (see fig. 58^). Pectorals inserted high up, not longer 



Fig. 58. Zenarchopterus dispar C. V. 



a male, b tailend of female X Vst '" posterior part of anal of male with 



enlarged and thickened 6th and seventh ray (magnified). 



than the head. Ventrals small, nearer to caudal than to head. 

 Caudal rounded or more or less truncate, never forked. Scales 

 moderate, deciduous. The scales on the back overlap each 

 other in two directions. In the anterior part each scale covers 

 with its anterior (cranial) border, part of the scale in front of 

 it, while in the posterior part just the opposite takes place, 

 and the posterior (caudal) border of the scales covers part of 

 the scale behind it, as is usually the case. At the point where 

 these two systems of overlapping meet, there is a central 

 scale, which overlaps the scale in front as well as that behind 

 it and remains uncovered itself. Lateral line running low down. 

 Gillrakers well developed. Third upper pharyngeals ankylosed. 

 Viviparous. 



Distribution: East coast of Africa, Madagascar, Sey- 



