NEW BRITISH HEN LEAS. 467 



circular or discoid when free. The dorsal vessel arises in 

 segment nine ; the segments eight, seven, six have an enlarged 

 pulsating vessel, which then contracts, and the blood appears to 

 be shot through the narrow portion. I could find no traces of 

 salivary glands, even in a rudimentary state, in any of the 

 specimens examined. The nerve is enlarged in the foremost 

 segments, and the pharynx is evertible, so that one can observe 

 it being used in taking in food. I noticed this peculiarity in 

 another species many years ago. 



The spermathecse, as usual in this genus, are destitute of 

 glands and diverticula. In one specimen I observed traces of 

 an enlargement of the duct about the middle, but usually the 

 organ is simple and uniform in size, and opens into the intestine. 

 This is one of the species which is destitute of oesophageal 

 glands. In one specimen the first nephridia were situated in seg- 

 ment five-six, but in other cases I could not trace them earlier than 

 six-seven. These organs are of great importance in diagnosis. 

 I find that they differ somewhat widely in this species. In the 

 front segments the anteseptai is often very brown and somewhat 

 large, while the duct springs from the anterior third of the post- 

 septal. Behind, however, the duct is a continuation of the 

 posterior end of the organ. It is then about two-thirds the 

 length of the postseptal. It frequently happens that many oil- 

 cells are present, and in one instance the rich yellow colour 

 gave a golden hue to the specimen. The ampulla, found in the 

 neighbourhood of the girdle in pairs, is very small, pear-shaped, 

 hardly longer than broad, while the duct is very narrow. It 

 will be seen that the new species in some respects resembles 

 H. tenella, Eisen (originally described as Archienchytrceus tenellus). 

 Eisen, however, does not distinguish two kinds of nephridia, 

 and the two present the following differences : — 



H. TENELLA, Eisen. 



Brain nearly as long as broad, 

 notched before and behind. 



Ampulla more than twice as long 

 as the middle is broad ; spindle- 

 shaped. 



Length 8-10 mm., with about 



H. PEEPUSILLA, Friend. 



Brain about twice as long as 

 broad, concave in front, convex 

 behind. 



Ampulla hardly any longer than 

 broad; pear-shaped. 



Length 2-3 mm., with about 



fifty segments. I thirty segments. 



