590 NATHAN FASTEN 



gave the best result for smears, the cells undergoing almost no 

 transformations in size and general appearance. 



This problem was undertaken during the fall of 1911 und^r 

 the direction of Prof. Michael F. Guyer, to whom the writer is 

 much indebted for kindly help and criticism. 



LITERATURE ON THE CYTOLOGY OF THE DECAPOD CRUSTACEA 



Considerable has been written on the cytology of the Decap- 

 oda, especially on the genesis of the spermatozoa. This is due 

 to the fact that the sperm of this group of Crustacea is so different 

 in shape and form from those found in other animals, belong- 

 ing to the type commonly known under the name of 'radial' 

 spermatozoon. 



Grobben ('78), was the first investigator to make a microscopi- 

 cal study of the sex organs of the decapod Crustacea. He worked 

 on Alpheus ruber, Palaemon rectirostris, Virbius viridis, Athanas 

 nitescens, Astacus fluviatilis, Homarus vulgaris, Galathea squam- 

 ifera, Eupagurus prideauxii, Eupagurus meticulosus, Pagurites 

 maculatus, Palinurus vulgaris, Gebia littoralis, Calliaxis adriatica, 

 Porcellana platycheles, Porcellana longicornis, Ethusa mas- 

 carone, Dromia vulgaris. Ilia nucleus, Stenorhynchus phalan- 

 gium, Inachus thoracicus, Maja squinado, Lambrus angulifrons, 

 Eurynome aspera, Pilumnus hirtellus, Portunus depurator, 

 Carcinus maenas. Pinnotheres veterum and Pachygrapsus mar- 

 moratus. 



Grobben gives an excellent review of the earlier literature. 

 From his review it is evident that earlier investigators had 

 dealt only superficially with the sex organs of the decapods. He 

 then describes in detail: (1) the structure of the testis, together 

 with its position and form in the various species; (2) the origin 

 of the spermatogonia, and (3) the development and structure 

 of the spermatozoon. He dwells particularly on the origin of 

 the spermatogonia. Upon examination of the tubules of the 

 testis during the early stages of proliferation one finds two types 

 of cells: (a) spermatogonia, containing large, round nuclei that 

 a¥e surrounded by a distinct mass of cytoplasm, and (b) irreg- 



