356 Mr. H. J. Carter on the Reproductive 



stage or small form, when tliey conld not be distinguished 

 from common granules, and then the " spermatoa " might 

 be confounded with the early stage of the ovum itself; while 

 in the Calcisponges they might be thus confounded with the 

 large cells of the embryo or larva, when these have become 

 separated from that body ; or, indeed, with the nucleated 

 granuliferous cells in the advanced segmentary stage of the 

 ovum generally, that is the yolk-cells, when the latter have 

 become extravasated by the bursting of the ovum. 



Again, the only means of distinguishing the " spermatoon " 

 in the sponges where it approaches in size that of the ampul- 

 laceous sacs is by the relative smallness of the spermatic 

 granules in the former and their want of definite arrangement, 

 which makes them look as if they were heaped together indis- 

 criminately ; hence probably the German term " Sperma- 

 klumpen." In this size and state also the " spermatoon " may 

 be easily confounded with the enlarged ovum, whose glistening 

 spherical yolk-granules at this period very much resemble those 

 of spermatozoa, especially if the germinal vesicle be hidden 

 or has just disappeared. 



Lastly, in the living state their presence in a matured con- 

 dition is so transient that, connected with the chance of tlieir 

 being present at all with this transitory condition, many 

 specimens might have to be examined before they are met 

 with, that is between the time of their being eliminated 

 in a matured state and their passage into the ovum ; while 

 the crucial test after all, viz. that of seeing them applied 

 to the ovum itself, has only been witnessed and represented 

 by one person, viz. Prof. Hiickel {op. cit. Atlas, Taf. xlviii. 

 fig. 6, Sycortis quadrangulata^ Grantia ciliata^ Bk.). 



I have above stated tliat, in the ovigerous specimen of 

 Cliondrosia sjnirca (which must now be regarded as my 

 ^^ Halisarca reticulata " in the " Supplement " to Mr. Wilson's 

 sponges, ' Annals,' 1886, vol. xviii. p. 274), I could find 

 nothing but ova^ that is, no spermatoid development; but the 

 opposite is the case in another specimen, where there appear 

 to be a great number of '^ spermatoa " and 7io ova. These 

 cells are spherical and about 2-6000tliS inch in diameter, thus 

 distinctly contrasting in size with the spongozoa of the neigh- 

 bouring ampullaceous sacs from the smallness of the latter, 

 while there is nothing else present of this kind with wliich 

 they could be confounded. In some instances they are dis- 

 tinctly nucleated and in others as distinctly filled with sharply- 

 defined, small, opaque, spherical granules, all of which are 

 about the same size. If this development is spermatic, then 

 the specimen must be viewed as producing the male elements 



