SPERMATOPJUORES IX EARTHWORMS. 419 



But if this be so, the whole question of the place of formation 

 of the spermatophore will have to be reconsidered. I have, indeed, 

 no positive facts concerning the reasons for the rounded outline 

 of the mass of spermatozoa. 



The arrangment of the spermatozoa requires some description. 

 They are not massed higgle<ly-piggiedy with the heads and 

 the tails pointing in any direction ; the arrangement is a 

 perfectly regular one. The heads of the spermatozoa are 

 all on that side of the sperm-mass which is nearest to the 

 "stalk" of the spermatophore. The upper part of the spenn-ball 

 is composed entirely of the tails, which are not disposed in 

 straight lines, but are waved and curved in every direction. 

 The heads radiate outwards in a quadrant or a little more 

 perhaps. The actual heads are in close contact with the walls 

 of the spermatophore, and some of them descend for a space 

 into the narrow duct of that organ. This rather looks as 

 if they were so disposed for easy egress at the time when the 

 sperm has to leave the spermatophore, which suggests that the 

 phagocytosis of the case is not a necessity for fertilisation. It 

 may be also that the spermatozoa escape, as Cognetti de Martiis 

 thought of the spermatozoa of Pareudrilus jjcdlidus, through the 

 actual membrane of the spermatophore case, the action of the 

 phagocytes facilitating their egress by widening the strands of 

 the wall. 



In any case the fan-like radiation of the heads of the spermatozoa 

 agrees with the idea that those which are more laterally placed, 

 and do not face the external spout-like orifice of the case, may 

 make their way out through the actual walls. 



In addition to the spermatozoa the spermatophore contains a 

 graniilar mass which fills up the available space above the delicate 

 case containing the spermatozoa. This granular mass has the 

 appearace of broken-down cells. A comparison at once suggested 

 itself with the granular substance described by Whitman in the 

 spermatophoi^es of Clejisine* . In the Leech, howevei-, the 

 granular contents of the spermatophore lie near to the external 

 orifice of the spermatophore, and seem to clear the way fi'om in 

 front of the subsequently issuing spermatozoa., or to perform 

 other functions which are discussed by Whitman. Like Whitman, 

 I was first disposed to I'egard the granular contents of the 

 spermatophore of Pherethna as being of a cellular nature. I 

 believe, however, that the substance is not composed of cells, 

 though probably of broken-down cells. 



The position of this granular mass at the apex of the spermato- 

 phore suggests that it may be of mechanical assistance t in 

 expelling the sperm, supposing that the latter is usually expelled 

 through the mouth of the spermatophore, and not liberated by 



* .Tonni. Morpb. vol. iv. p. 361. 



t See also Brumpt, " Reproduction des Hiiudinees," Mem. Soc. Zool. France, 

 1900, p. 286. But Kovalevsky (Coniptes Eeiidus, vol. cxxix. 1899, p. 261) did 

 find cells which he regarded as phagocytes to eat the spermatozoa. 



