628 



the first is simpler as well as smaller and is perhaps immature. In 

 Hyperiodrilus the last of the three is simple in structure. In the XIII. 

 segment is a pair of massive calciferous glands, which have ciliated 

 ducts leading into the oesophagus ; from this point onwards the lining 

 epithelium of the gut is ciliated. The four posterior pairs of hearts are 

 connected with the dorsal vessel and with a supra-intestinal trunk; the 

 latter lies, as does the dorsal vessel of Deinodrihis'^, in a special coelo- 

 mic sac, which is, however, not continuous through the septa. 



The testes are two pairs in segments X, XI. They are attached , 

 as in Acanthodrilus annectens'^ alone among Earthworms, to the an- 

 terior side of the septum. Each testis is enclosed in a sac, which also 

 contains the dilated portion of the vas deferens. 



As in Teleudrihis and Hyperiodrilus each vas deferens perforates 

 the septum twice, as the funnel lies enclosed in the spermsac which 

 depend from the posterior surfaces of septa X/XI and XI/XII. 



The atria are very long and would occupy if they lay straight 

 a dozen segments or so. Each atrium has distally the usual structure 

 which belongs to atria of this type ; it is here covered by a very thin 

 layer of muscles. There is no marked subdivision of the atrium into 

 two regions, but the epithelium gradually decreases to a single layer of 

 cells consisting of large glandular cells and of smaller packing cells; 

 at the same time the muscular layers get slightly thicker and are divi- 

 sible into an outer circular and an inner longitudinal layer. The two 

 vasa deferentia of each side open separately into the more distal portion 

 of their atrium. There are no penial setae. 



The female reproductive organs are quite as remarkable as in 

 Hyperiodrilus though rather different. 



There is a single spermatheca, which is of considerable size, 

 and lies to the right of the oesophagus in the XHI. segment; it com- 

 municates with the exterior by a narrow duct which runs forward 

 beneath the nerve cord and opens on to the XI. segment. 



The ovaries are enclosed in special sacs which communicate 

 directly with the eggsacs ; that of the right side of the body also com- 

 municates by a very narrow prolongation with a spacious sac lying on 

 the dorsal side of the oesophagus ; into this projects the extremity of 

 the spermatheca, which is therefore partially enclosed by the sac, and 

 not entirely as in Hyperiodrilus. 



The mature ova are surrounded by a thick radiately striated 

 membrane, as in Hyperiodrilus. The oviducts open on to the XIV. seg- 



2 Quart. Journ. Microsc. Sc. Vol. XXIX. PI. XIII tìg. 0. 



3 Quart. Journ. Microsc. Sc. torn. cit. PI. XII üg. 13. 



