908 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [30] 



In Telmatodrilus the posterior margin of the cephalic ganglion projects 

 in a very sharp angle, and the processus formed is partially forked, per- 

 haps the result of being attached to two different muscular bands. 



In all the other species of this family both margins of the cephalic 

 ganglion are concave in smaller or lesser degree, and the differences in 

 the ganglion of the different species are mostly actuated by their own 

 size and form and by that of their lateral cephalic projections. 



In some species, such as Limnodrilus Silvani and Limnodrilus alpestris, 

 the posterior upper part of the cephalic ganglion is sometimes three-lobed. 

 The third or the middle lobe, however, was not present in all the speci- 

 mens, and never in immature forms. 



The lateral globular swellings of the cephalic ganglion of Uyodrilus 

 sodalis are also worthy of mentioning, but for this as well as other minor 

 variations of the ganglion I must refer to the descriptions given under 

 the headings of the different species. 



F.— GEIfERATIVB SYSTEM. 



In no class of animals are the generative, or especially the copulative, 

 organs so complicated and so remarkable for their delicate structure as 

 in the family of TubiJicidcB. These organs consist here, as in other 

 families of Oligochseta, of two classes, viz, reproductive and conductive. 

 Each of these classes can further be divided into male and female. 



The reproductive organs are — 



1. Male: Testes. 



2. Female: Ovaries. 



The conductive or receptive organs are — 



3. Male : Efferent duct and copulative organs. 



4. Female : Oviducts and receptacles. 



• Of these the lower end of the efferent duct, or the copulative organ 

 proper, penis, is invaginated in the oviduct, and both form, so to say, 

 one single but rather complicated organ. Both will therefore be con- 

 sidered together. 



TESTES. 



These organs consist of one or several large, sack-like, amorphous 

 bodies, situated either in front or behind, or sometimes both in front and 

 behind, the cingulum (segment containing the efferent duct and oviduct). 

 In Telmatodrilus we find one pair of testes occupying the eighth and 

 ninth setigerous segments, one testicle on each side of the ventral 

 ganglion. In this genus no testes are found behind the cingulum. 

 In TuMJicini the testes are generally situated behind the cingulum or 

 copulative organs. They consist either of one single sack-like testis^ 

 extending through several segments, or of several small ones more or 

 less connected with each other. In Uyodrilus sodalis the testes occupy 

 ten segments, beginning in the twelfth and extending to the twenty- 

 second setigerous segment. They seem in this species not to be con- 

 nected with each other. In IlyodHlus Perrierii they occupy four seg- 



