1903.] FROM ZANZIBAR AXD BRITISH EAST AFRICA. 109 



The genus may be defined very briefly as follows : — Lepto- 

 planoid with flattened leaf-like body. A pair of long muscular 

 vesiculae seminales, which lie parallel to the median ductus 

 ejaculatorius and penis and receive the vasa deferentia of either 

 side respectively at their hinder ends. 



Haploplana elioti, gen. et sp. nov. (Plate IX. fig. 4.) 



Two specimens dated 25.3.01. One of them is immature; the 

 other, from which I prepared sections, is in a late stage of sexual 

 activity, and the centre of the body is crowded with eggs. The 

 body is oblong, about 6 mm. in length, 3 in breadth, with rounded 

 ends. In places it is as much as 1 mm. in thickness. 



The eye-spots are arranged in two irregular lines lying over the 

 brain on either side of the middle line. They are not numerous 

 (text-fig. 6). 



Text-fig. 6. 



Saploplana elioti, sp. nov., magnified and (b) natural size. 



On the dorsal side the epithelium contains a number of pseudo- 

 rhabdites. On the ventral surface close to the margin there are 

 numerous small rhabdites on either side, but these do not occur 

 elsewhere. The basement-membrane is thin, and the muscles of 

 the body- wall are very feebly developed. On the dorsal side these 

 consist of a narrow longitudinal layer followed by a few circular, 

 fibres. On the ventral side there is an additional inner longi- 

 tudinal layer. The dorso -ventral musculature is well -developed. 

 The ovaries are dorsal, the testes ventral. 



The pharynx is of a very simple type ; it consists of a fold 

 projecting from the middle of the wall of the oval pharyngeal 

 pouch, the longer axis of the pouch coinciding with the main axis 

 of the body. The opening into the gut lies rather in front of the 

 opening to the exterior, which is about at the middle of the pouch 

 (see PI. IX. fig. 4, p/i.«.). 



The gut-branches are numerous and appear to undergo anas- 



