[45] OLIGOCH^TOLOGICAL RESEARCHES. 923 



end. The tails of the spermatozoa extend outside of the main body of 

 the spermatophore. 



lu some spermatophores the tails are more numerous in one end than 

 in the other. (See Limnodrilus Silvani and L. alpestris.) 



lu TuUfex campanulatus the spermatophore was surrounded by a large 

 pellucid bag, which, perhaps, also may be the case in other species. 



b. The spermatophore is more cylindrical and not covered with the 

 tails of the spermatozoa. Such is the spermatophore of Tuhifex cocci- 

 neus.* 



c. The spermatophore extremely long and narrow, coiled into a kind 

 of spiral and surrounded by a large pellucid membrane. The exterior 

 is here seemingly divided in numerous oblique segments. Such a sperm- 

 atophore is found only in Spirosperma. 



The form of the spermatophores is more or less variable, and can 

 only exceptionally be of any value as a specific or generic characteristic. 

 Only in Spirosperma the spermatophores appear to be of a more constant 

 form, and in fact resemble each other closely. 



G.— SEGMENTAL OEGANS. 



The segmental organs in Tubificidw, and in fact in all the families of 

 Oligochceta, open in front of the ventral spines. They are found in all 

 the setigerous segments, except in 1st to 5th or 1st to 6th, and in 8th to 

 10th or even 8th to 11th. It is evidently this absence of segmental 

 organs in those segments which are occupied by the sexual conductive 

 organs which first gave impulse to the theory advanced by Claparede 

 and others that the conductive sexual organs were nothing else than 

 modified segmental organs. Vejdovskyt has, however, shown that in 

 Encliytrceidm the conductive sexual organs have a quite independent 

 origin, and considers the same to be the case even in Naididce. It 

 seems out of the question to assume that the segmental organs and 

 receptaculum seminis are homologous anywhere in this class of Anelida, 

 as there is little doubt as to their different origin, but concerning the 

 efferent duct the question must as yet remain open, no direct observa- 

 tions having been made on the origin and development of the segmental 

 organs of Tuhijicidm. The efferent duct in this family seems to originate 

 and develop on a quite different way from what it does in Enchytrceidce, 

 and when this is the case the relationship between those respective 

 organs and the segmental organs may also be quite different in the dif- 

 ferent families, and in any case we must regard the question as as yet 

 unsettled and requiring a good deal more direct observation than I have 

 had opportunity to make. I hope at a future time to be able to return 

 to this subject, and will at i^resent restrict myself to a description of 

 the organs in question as they are found in this family. 



The segmental organs of Tuhificidce resemble those of Lumhriculidce 



* Fejdovskij ; Ueber Psammoryctis, Taf. VIII, Fig. 13. 

 i Mono^raphie der Enchytr widen, page 40, «fcc. 



