— 143 — 



is pointed. Two spicula of equal size. Gubernaciilum is absent. 

 Several pairs of preanal and postanal papillae present. Vulva 

 near the middle of the body. Oviparous. Parasites of Inver- 

 tebrates. Type: Isacis migrans Lespes. 



21. Isacis multipapillata nova spec. 



Host: lulus sp. 



Occurence: posterior part of intestine. 



Body cylindrical,. of white colour, smooth, without any traces 

 of striation, slightly narrowing towards both ends; the ante- 

 rior end bluntly rounded, the posterior — terminating by a 

 small .pointed appendage. Mouth-opening surrounded by 6 

 undulating cuticular formations which constitute a shallow 

 cavity, at the bottom of which are arranged 3 chitinous irre- 

 gular triangular plates surrounding the entrance to the oeso- 

 phagus. The structure of these plates is very peculiar: each 

 has an exterior edge, the base by which the plate is attached 

 to the underlying tisues, and an interior convex edge turned 

 towards the oral aperture. This latter edge is covered with 

 several large, sharp chitinous denticles, and a whole series 

 of minute ones, which give this organ the aspect of a comb. 

 There are about 8 spear-shaped processes on each lip, some 

 of them being bidentate. It is impossible to state exactly 

 the number of minute denticles— there are some scores of 

 them and they are arranged in several rows, as it is seen 

 in the figure drawn from a preparation in which the edge 

 of one lip was turned outwards, thus opening part of its 

 interior surface, which is covered with several rows (3 — 4) 

 of denticles. The oesophagus consists of 2 parts: a more elon- 

 gated anterior and a posterior part (the bulb). The anterior 

 part has the form of a truncated cone with a wide base. The 

 posterior part — the bulb —is cordiform with the apex directed 

 to the intestine and inserted in the latter, forming a kind of 

 ventriculus. Inside the bulb there is a chitinous denticular 

 apparatus, composed of three plates the anterior part of which 

 has a rough, striated surface. The intestine is somewhat 

 wider than the apex of the bulb in its anterior portion, on 

 account of which it envelopes part of the bulb in the form 

 of a case. 



The male. Entire length of male 3,57 mm., at a maxi- 

 mum width — 0,187 mm. The length of the entire oesophagus 



