1904.] EARTHWORMS PROM NEW ZEALAND, 231 



SO that, on segment 21, ah is only ^ ah in the mid-body segments, 

 and in the subclitellar segments [e. g. 16th) it is even less. At 

 the same time the ventral gap (aa) enlarges, so that h keeps in its 

 line, while a moves outwards. In the preclitellar region this 

 increased gap remains, and the lateral and dorsal gaps are also 

 larger, but the gaps ah and cd remain the same size as in the mid- 

 body ; in other words, the rather increased diameter of the pre- 

 clitellar region affects the interchsetal zone, and not the chfetal 

 spaces themselves. 



I measured the spaces on the body by means of dividers, with 

 the following results : — 



Put in the iisual formula for the mid-body, starting mth 

 the smallest gap, 



cd < ah <hc< aa : aa = 2cd : dd = 2 aa = B he. 



On segment 17 the ventral cha^tee are replaced by two long, 

 delicate penial chsetse. 



The clitellum is saddle-shaped, and though the annuli and inter- 

 segmental furrows are quite evident ventrally, there is no distinct 

 latero- ventral margin such as exists in Litmhricus &c. The 

 glandular tissue extends down to the line of chteta h. The cli- 

 tellum extends over the six segments 13-18. 



Genital pores, &c. — The male pore is on segment 17, situated 

 on a low, rounded, and slightly prominent porophore in line with 

 the chsetal gap ah. The pore itself is nearly in line with h, and 

 the penial chaetpe project therefrom. 



Tuhercula puhertatis are well-developed, in the form of a series 

 of transversely disposed, paired oval pads (text-fig. 48, p. 232) 

 situated on the hinder regions of the segments 12,13, 14, 15, and 19, 

 20. These pads are developed from the last annulus of the segment 

 in each case, but the last two pairs appear to be intersegmental, 

 owing partly to the contraction of the worm, and partly, perhaps, 

 to their size. These tubercles have not all the same position 

 relative to the chsette : those of the 12th, 19th, and 20th segments 

 extend from the level of h inwards nearly to the middle line, while 

 the other three pairs, on segments 13, 14, 15, extend from cheeta a 

 and almost touch in the middle line. 



There is a single pair of spermathecal pores on the intersegmental 

 groove 7/8, in line with h. As a matter of fact, each pore is 

 double : i. e., the main sac and its diverticvilum open independently 

 one above the other, but close together, in the furrow. 



I was unable to detect either dorsal pores or nephridiopores by 



