28 HARLEY N. GOULD 



The adult apyrene sperm is shorter, in relation to the eupy- 

 rene, than in many other Molluscs where it has been reported. 

 The apyrene sperm measures about 0.05 to 0.06 mm., the eupy- 

 rene about 0.16 to 0.17 mm. 



As has been shown, the apyrene spermatoblasts are derived 

 from cells which cannot be distinguished from the spermatogonia 

 of the true sperm; yet their development is in no way parallel 

 to that of the latter; there are no divisions of the spermatoblast 

 after it has been differentiated. About the only suggestions of a 

 relation with the spermatogenesis of the eupyrene series are, 

 first, the occasional attempt by the spermatoblast nucleus to 

 form a pachytene thread; and second, the slight resemblance of 

 some of the karyomerites to the chromosomes of the first matura- 

 tion division. The course of development in Crepidula, in the 

 early stages at least, is more nearly like that of Strombus as 

 described by Reinke, than like any other that has been de- 

 scribed hitherto; yet Reinke has traced the apyrene spermato- 

 blasts of Strombus to the 'basal nuclei' and does not consider 

 them similar to the spermatogonia. 



The present writer desires only to add the facts which have been 

 observed in his material to the literature of this subject, in the 

 belief that a sufficiently wide comparative study of atypical 

 spermatozoa will eventually reveal their true significance. What- 

 ever part they play in life processes, if any, they are interesting 

 to one who would study the behavior of non-nucleated motile 

 bodies of protoplasm. The writer feels also that the knowledge 

 of atypical spermatozoa is not yet sufficiently inclusive to war- 

 rant dismissing them as mere ' f unctionless reaction-products.' 



The adult testis 



The testis, consisting of many lobules or follicles, shows great 

 variation in size and in activity in different individuals. In the 

 most active condition all the stages ot spermatogenesis and of 

 apyrene sperm development are found in a single specimen. 

 The spermatogonia are more numerous at the periphery of the 

 gonad, the later stages near the center. When new spermato- 



