314 



BULLETIN OF THE BUREAU OF FISHERIES. 



In the following description of the genesis and structure of the sperm cell of the 

 lobster, I shall follow in the main the account of Koltzoff {172), from which I have con- 

 structed a number of diagrams (fig. 31, j-5, and fig. 32). This accoimt, whether correct in 

 all particulars or not, is at least intelligible, and we are able to understand the remarkable 

 evolution in form which these cells undergo in consequence of changes in osmotic pressure. 

 It is very different from that of Sabatier, who devotes 37 pages to the sperm cells of the 

 lobster, yet leaves it difficult to understand his descriptions and impossible to construct 

 any consistent diagrams from his figures. 



fAeffinp.ch. 



cap. 



tn.p. 



Fig. 31. — Diagrams of sperm cells of the lobster before (i), during (2), and after (3) capsular explosion, based upon Koltzoff (see 

 172). a a, plane of section in figure 36; a. ch., anterior chamber; deb, distal central body; Ex. sub., external layer; in. i., 

 inner tube; fned. t,, medium tube; n. proc, neck process or ray; p c b., proximal central body; p. ch., posterior chamber; 

 p. mb., outer protoplasmic (?) membrane. 



According to Koltzoff the sperm cell is derived by metamorphosis from a spermatid 

 which in turn arises by division from a spermatocyte of the testis. The centrosome 

 divides into two parts, and for some time remains united by fibers to the nucleus. The 

 cell body is stuffed with granules which exhibit a difiference in staining power, and in 

 fact become differentiated into two important parts of the sperm, the mitochondral 

 body and the capsule. 



In the course of these changes the mitochondral becomes pressed against the 

 nucleus, and molded upon it. A vesicular sperm cell is thus formed, DecuUar to the 



