BY WILLIAM A. HASWELL. 431 



part of the intestine : they are narrower than the posterior pair 

 and are laterally compressed. The right and left vasa deferentia 

 meet as usual in a peai'-shaped vesicula seminalis connected with 

 the bulb of the penis by a narrow ejaculatory duct. 



The penis (fig. 2) is of a simple character. The tubular part 

 is only slightly curved. The introvert is not very sharply marked 

 off from the penis itself : in its interior are a number of long fine 

 spines with a number of shorter spines round the margin. 



This species was found in the branchial cavities of Astacopsis 

 tasmanicus in small streams near Hobart, Tasmania, sometimes 

 coming out on the outer surface of the Crayfish. Its eggs are 

 attached to the bases of the gills. 



In many respects this species resembles its much larger con- 

 gener, T. quadricornis, which is also an inhabitant of Tasmania 

 (living on the surface of the large Crayfish, Astacopsis Franklinii, 

 that inhabits the northern rivers of that colony). In addition 

 to the absence of pigment and of eyes in T. tasmanica, it differs 

 from T. quadricornis in the structure of the penis, the spines of 

 which are much less numerous, and less elaborately arranged in 

 the former than in the latter. 



Temnocephala aurantiaca, n.sp. 

 (Plate xxii., fig. 3.) 



This species is of about the same size as T. tasmanica, and 

 resembles it in all its external features, except that the integu- 

 ment contains an orange-coloured pigment and there is a pair of 

 eyes. The tentacles are of essentially the same form. The penis, 

 (fig. 3), however, is entirely different. The tubular portion is 

 more strongly curved and the introvert more sharply marked off. 

 The introvert is armed with numerous extremely fine spines. 



This species was found on the lower surface of the abdomen of 

 a species of Astacopsis, at present undetermined, that is found in 

 burrows in damp ground in the neighbourhood of the Dee River 

 towards the centre of Tasmania. ' 

 inner surface of the branchiosteo-ite. 



