328 Anatomical JVotes on Sutroa Alpestris. [zoe 



as he supposes.^ As the spermatophore is ah'eady formed in the 

 sperm-sacs, .it is evident that neither the prostata or the spermathecae 

 contribute to its formation. It is far more likely that the glandular 

 part of the spermatheca produces a secretion which dissolves the 

 spermatophore and separates the spermatozoa. The cell-wall in the 

 spermatophore is the primary part, the spermatozoa forming in the 

 interior of the cell. At a later stage of development the tails of the 

 spermatozoa protrude through this cell-sac, their free ends forming 

 a ciliated appendix on one side of the spermatophore (Fig. t8). 

 These protruding parts of the spermatozoa are at this stage beauti- 

 fully wavy or screw-like and very stiff. At a later stage these screw- 

 like cilice elongate themselves, or rather their extreme free ends 

 grow out, forming the tails of the spermatozoa. This later devel- 

 oped part of the tail is not screw-like, and the division between the 

 two parts is so very distinct that at a superficial examination it 

 appears as if it constituted two distinct and separate bodies (Figs. 19 

 and 20). In the full grown spermatozoon this screw-Uke part is 

 about one-eighth or one-tenth part of the whole (Fig. 23). 



The ovaries or ovisacs are situated far behind the sperm -sacs in 

 somite XXXII, one on each side of the ventral nerve ganglion. As 

 regards their structure, they do not materially differ from the ovaries 

 in Rhynchelmis as described by Vejdovsky (I c, page 353). In 

 one specimen I found the ovary in segment XXXII, but I am 

 inclined to think that their position sometimes varies with the size of 

 the worm. Ripe ova surrounded by numerous fatty agglomera- 

 tions are frequently seen moving freely in the anterior somites in 

 the vicinity of the oviduct, which is situated in somite X.- 



Spermiducal organs. These consist of one pair opening 

 into a common atrium (Fig. i). The atrium is furnished with 

 a large prostate gland extending through at least seven somites, 

 commencing in somite XII and ending in XVIII, thus leaving 

 three segments of the atrium free (IX, X and XI). The atrium 

 opens into a copulatory papilla, which latter opens externally in the 

 center of segment IX behind the ventral setce. The atrium ex- 

 tends through ten somites, from IX to XVIII. The exact place 

 where the efferent ducts enter the atrium I have not been able 

 to ascertain, but most probably this takes place in the extreme pos- 



"Vejdovsky, Syst. des Oligochxtcn, I. c, page 153. 



