DESCRIPTIONS OF EARTHWORMS. 295 



beginning between the 5th and 6th ring. The clitellum 

 consists of 6 well-defined segments , extending from the 

 25th — 30th ring; a ridge of genital tubercles is present 

 on segment 26, 27, 28 and 29. The setae are protruding 

 strongly out of the bodywall and are furnished on their 

 distal portion with small arches , resembling the bristles 

 of Criodrilus. They are arranged in eight series , separated 

 by a rather large space from each other; the medial lateral 

 interval is as large as the superior lateral , but smaller 

 than the inferior lateral interval , which is about as large 

 as the ventral one. The dorsal interval is nearly twice as 

 broad as the ventral one. 



The number of copulatory pouches varies in the different 

 specimens. One individual has four pairs of them, in the 

 7th, 8th, 9th and 10th segment, situated in front of the 

 posterior septum ; their external apertures lie in a line with 

 the superior dorsal setae. The second specimen has but 

 three pairs of copulatory pouches in the 8th, 9th and lOth 

 segment, and the third specimen has only two pairs of 

 them, those of the left side situated in segment 7 and 8, 

 those of the right side in segment 8 and 9. It appears 

 therefore to me that four pairs of copulatory pouches is in 

 all probability the typical number in fully-developed spe- 

 cimens. This is not the first time that a variation is ob- 

 served in the number of copulatory pouches, for Beddard 

 tells us ^), that he examined a Pmc/iaé to- species from Ma- 

 nila, in which these organs varied in number in the most 

 extraordinary way and the same author stated several va- 

 riations in the number of spermathecae in Perionyx exca- 

 vatus ^). 



There are three pairs of vesiculae seminales in segment 

 9, 11 and 12; the first pair of them is fixed to the an- 

 terior, the second pair to the posterior septum of the 10th 



1) Observations on the structure of L. complanatus Duges; Proc. R. Soc. of 

 Edinburgh, 1885—86, p. 453. 



2) Proc. Zool. Soc. of London, 1886, p. 308. 



Notes from the Leyden ]>Xu.seuixi, Vol, IX. 



