380 Mil. F. E. BEDDARD ON THK [Apr. 19, 



indica ' this naturalist plainly perceived that the structure of tlie 

 male generative glands in Perichcsta was essentially .-imilar to that ot 

 Luinbricus. Mr. iienljam ' was also aide to discover the true testes 

 in Microch(£ta, situated on the anterior wall of the segments which 

 contain them, and enclosed in a common tac with the vesiculae senu- 

 iiales and the terminal funnels of thevasa defeientia. More recently 

 Dr. Bergh^ has given a full account of the male reproductive organs 

 of Pericliceta, which establishes without any doubt the correctness of 

 ilorst's observations. 



lnii'«r//7'^M*' there are three pairs of white glandnlar-Iooking bodies 

 in segments 10, 11, and 12, which evidently correspond to the 

 structures termed testes by Perrier in his notes on tlie anatomy of 

 this genus \ \\\ the dissected worm these bodies were very friable ; 

 and for that reason I have found it impossible to give an accurate 

 idea of their naked-eye appearances. Tiiese bodies are not testes, 

 but vesiculae seminales ; tlieir structure resembles that of the vesiculse 

 semiuales of Lumbricus (fig. 1 1, «) ; they consist of a delicate fibrous 

 network of trabeculse, in the compartments of which are lodged the 

 developing spermatozoa. In the case of tbe two anterior pairs of 

 vesicnlse seminales, the fibrous sheath of ttie organ was found to con- 

 tain (fig. 2, t) a small irregularly-shaped body composed of small 

 uniformly-sized cells ; these bodies were attaclied firndy to the 

 ensheathing fibrous tunic, and at one point the fibrous tunic was seen 

 to be continuous with the intersegmental septum close to tbe nerve- 

 cord ; and here the cellular body appeared to be attached also to the 

 mesentery. These two pairs of organs seem to le without doubt the 

 true testes. Tiieir po-ition, attaclied to tie anterior wall of segmeiits 

 10 and 11, as well as tl eir enclosure by the tunic of tlie vesicuise 

 seminales, is entirely in favour of such an identification. 



In both the lOtb and 1 1th segments the vesiculae seminales were 

 united by a median unpaired region, lying beneath the alimentary 

 tract and enclosing the ventral blood-vessel, but not the nerve-cord ; 

 it is with this portion of tlie vesiculae that the funnels of the vasa 

 deferentia are connected, as v\ill be des ribed shortly. In tbe case 

 of the anterior pair of vesicuhe this median legiou was closely packed 

 v\ith bundles of developing spermatozoa ; tbe median region of the 

 lltli segment, on the contrary, was nearly empty of developing 

 spermatozoa. 



The two vesiculae of the 12th segment do not enclose any testis ; 

 they appear to be unconnected \*ith the \esiculae of ihe t^o anterior 

 segments ; they are in all probability, however, to be regaided as 

 outgrowths of the latter, and not as constituting an independent 

 third pair of vesiculae. 



It is important to notice that Eiuhilus, although so abnormal in 

 the structure of tiie female generative apj)aratus, conforms to the 

 ordinary type in the structure of tbe male generative organs. The 

 facts detailed above, coupled with the researches of Horst, Benham, 



' Niedei-1. Arohiv f. Zool. Ed. iv. (1877-78). 



^ Quart. Journ. Mit-r. Sci. vol. xxvi. (new series.) 



' Loc. cit. * I.oc. cit. 



