43 



lined with a low layer of naked cells. On those places, where the 

 eggs are lying, the wall of the receptaculum becomes very dilated 

 and represents only a delicate membrane. The receptaculum ovorum 

 is not immediately connected with the oviduct, and its opening lies 

 somewhat inward from the funnel of this duct (PL III. fig. 20). 



There is a large number of spermathecae in segment XIV — XIX. 

 Their number in different segments however is not constant and 

 varies from 1 to 3 pairs, nor do we find in the same segment 

 always the same number on both sides; sometimes the one side pos- 

 sesses two , the other side three of them. Usually I met with 1 pair in 

 segment XIV and with 3 pairs in segment XV — XIX, the total number 

 thus amounting to 32. The spermatheca of segment XIV corresponds 

 to the middle one of the three in the succeeding segments (fig. 16). 



The spermathecae are situated in the anterior region of each 

 segment and open on to the exterior in the intersegmental groove 

 of the segment and its preceding one. In some specimens the first 

 spermatheca lies precisely at the place, where the septum between 

 segment XIII and XIV arises, so the pouch is separated by a 

 constriction in two diverticula, of which the anterior is situated in 

 segment XIII, the posterior in segment XIV. A similar arrangement 

 was observed by Mr. Beddard with some of the spermathecae of L. 

 complanatus l ). The two superior spermathecae of each side have their 

 external opening next to the setae of the dorsal couple, the inferior 

 of them opens on to the exterior in the middle of the lateral region. 



Each spermatheca represents a globular pouch, lined with a single 

 layer of columnar cells; at the median side of the pouch this epithe- 

 lium appears to be lower than at the lateral side. 



It is a curious fact, that in several specimens no spermathecae 

 could be observed, though the clitellum was very obvious and the 

 worm possessed well-developed seminal vesicles and ovaria. 



A similar statement was made by Mr. Beddard with a specimen 

 of P. posthuma 2 ). Others of our specimens, with the clitellum 

 scarcely visible and without puberty-grooves, showed on transverse 

 sections only two spermathecae on each side, situated in segment 

 XV — XVIII; they contained no spermatozoa. Only the segments XI 

 and XII possessed developing seminal vesicles , containing unsegmented 



1) Proc. Royal Society of Edinburgh, 1885—86, p. 451. 



2) Anuals and Magaz. of Nat. History, 1886, p. 94. 



