380 MR. r. E. BEDDARD ON THE [-^l""- 19, 



indica ' this naturalist plainly perceived that the structure of tlie 

 male generative glands in PericluEta wa-; essentially .-iiiiilar to tliat ot 

 Luinbricus. Mr. Benliam " was also able to di-scover the true testes 

 ill Microchchta, situated on the anterior wall of the segments which 

 contain tliem, and enclosed in a common cac with the vesiculae semi- 

 iiales and the terminal fuimels of tlie vasa defeientia. More recently 

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

 of Perichceta, which establishes without any doubt the correctness of 

 Horst"s observations. 



{\\Eudrdust\\QVQa,ve three pairs of white glandular-looking 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 \ In 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. 'I'hese bodies are not testes, 

 but vesiculae seminales ; their structure resembles that of the vesiculse 

 seminales of Lumbricus (tig. 1 1, «) ; they consist of a delicate tibrous 

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

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

 vesiculae seminales, the fibrous sbeath of the organ was found to con- 

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

 uniformly-sized cells ; these bodies were attached firmly to the 

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

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

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

 mesentery. These two pairs of organs seem to l,e without doubt the 

 true testes. Their po-ition, attached to tie anterior wall of segmeiits 

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

 seminales, is entirely in favour of such an identification. 



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

 united liy 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 the vesiculae that the funnels of the vasa 

 deferentia are connected, as will be des ribed shortly. In the case 

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

 with bundles of developing spermatozoa ; the median region of the 

 llth 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 with the vesiculae of ihe t"0 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 EurliiUis, although so abnormal in 

 the structure of the female generative apparatus, conforms to the 

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

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



> Niederl. Arohiv f. Zool. Bd. iv. (1877-78). 



^ Quart. Journ. Micr. Sci. vol. xxvi. (new series.) 



' Loc. cif. * Loc. cif. 



