COMPAKATIVE STUDIES IX CKUSTACEAN 

 SPEKMATOGENESIS. 



M. LOUISE NICHOLS. 

 With 3 Plates and 12 Text Figures. 



This study was undertaken in order to determine how far typed 

 of the class Crustacea, showing in the adult condition well marked 

 morj^hological differences, would also present in the development 

 of the germ-cells characteristic dissimilarity. Accordingly, an 

 examination was made of the following forms : the Amphipod, Talor- 

 chestia longiconiis, the Isopods, Oniscus asellus Linn, and Idotea 

 irrorata, the Decapods, Hippa talpoides, Astacus fluviatilis and 

 Homarus vulgaris. 



There is much variety among the Crustacea with regard to the 

 appearance of the spermatozoa and an increasing complexity of struc- 

 ture from the lower to the higher forms. A comparison of the 

 spermatozoa makes, therefore, a convenient beginning for a study 

 of this nature. 



Speematozoa. 



Entomostraca. Phyllopoda. Zacharias (1893) has studied the 

 spermatozoa of the Daphnid Polyphemus. They are amoeboid in 

 shape, the character of the pseudopodia varying with the nature and 

 density of the solution in which they are placed. In a cell so sim- 

 ple, of course no distinction can be made between head, middle- 

 piece and taiL (Text Fig. 1.) 



Cirripedia. In the spermatozoa of Lepas anatifera L. and Bal- 

 anus improvisus Darw. Ballowitz (1908) was unable to discover 

 any part taking the characteristic nuclear stain of alum carmine. 

 The cell by teasing, however, could be separated into fibrils one of 



The Journal of Morphology. — Vol. XX, No. 'A. 



