Oligochaeta.] SUBANTARCTIC ISLANDS OP NEW ZEALAND. 261 



Fam. ENCHYTRAEIDAE. 

 LuMBRiciLLUS, Oersted, 1844. 

 Lumbricillus intermedius, sp. no v. (Plate X, figs. 8-11.) 



A littoral species, dull opaque-white in formol, with pinkish clitellum. The 

 worm is relatively stout, with well-marked segments, The body-wall is thick, owing 

 to the depth of the longitudinal muscles, which are about three or four times as 

 thick as the rest of the wall. The cuticle is thin. 



Dimensions. — From 10 mm. to 20 mm. in length, with a diameter of 1-1-25 mm. 



Prostomium rather long, about equal to the first 2 segments together ; with 

 blunt rounded tip, and broad base. 



The chaetae are in groups of 4-5 dorsally and 5-7 ventrally in the fore part of 

 the body ; one less — i.e., 3^ and 4-5 respectively — in the hinder segments. Feebly 

 sigmoid. 



Clitellum completely surrounds the segments (| 11), 12, 13. These latter are 

 longer than the neighbouring segments. 



Genital pores in the usual position. 



Internal Anatomy. 



The longitudinal muscle-layer of body-wall is about four times as thick as the 

 epidermis -I- the circular muscles. 



The dorsal vessel rises far back, at the 17th segment. I made no observations 

 on the distribution of the anterior vessels, this being a very difficult matter to study 

 in sections or preserved worms. 



Coelomic corpuscles are spindle-shaped. 



The oesophagus passes quite imperceptibly into the intestine. Septal glands 

 lie in the 4th, 5th, 6th, and '7th segments. The presence of the glands in the last 

 appears unusual ; but I examined and found them in several specimens, both in 

 section and in entire worms. 



Nephridium with a somewhat ovoid post-septal body, with duct rising from the 

 posterior end, and passing sharply forwards below it to the pore (Plate X, fig. 11). 



The genital organs lie in the usual segments. The testes are digitiform, and 

 of large size. The long funnel occupies the entire segment ; its length is about 

 five times its diameter ; it is bent slightly at its hinder end (Plate X, fig. 10). 

 The penis has the typical structure, a gland with muscular wall, opening by a wide 

 mouth on 12 ; the sperm-duct enters this on its median side. Retractor muscles 

 also pass from it to the body-waU. 



Sperm-sacs in 10, 12. 



The ovary is also lobulated, and large ova occupy the 13th. The oviduct is out 

 of all proportion small — little more than a pore in the ventral wall of 12 — with 

 scarcely any fimnel. 



The spermatheca in 5 has a wide duct, not marked off distinctly from the ampulla, 

 opening through a group of glands at 4/5. The pyriform ampulla narrows as it 

 approaches the oesophagus, and then is suddenly constricted, entering the gut by 

 a very small pore provided with a sphincter muscle (Plate X, fig. 8). 



