LYCASTIS OUADRATICEPS. 



379 



series but always toward the middle. Likewise, the sperm-masses 

 are always most numerous away from the terminal somites of the 

 spermatogenous series. 



It would be instructive to compare these ova with those of 

 other species of Lycastis. Unfortunately, the material is not at 

 hand to make a general comparison ; but it may be not out of 

 place to mention that the eggs of Lycastis hawaiiensis are not 

 only much smaller (. 1 5 mm. in diameter) but have a very dif- 

 ferent nucleus. It is one of the most beautiful examples of a 

 naked nucleus one could expect to find. The nucleoplasm is 

 directly and plainly continuous with the cytoplasm, and the con- 

 tact of yolk-grains give the nucleus an irregular, almost stellate 



t. 



O 



in.-' 



Fig. 5. Section through same specimen, and nearly same region of body, as Fig. 

 3. "Testis" (t) and ovum (o) appressed to the intestine [in). A few bunches 

 of sperm cells (spermatocytes?). X II2 - 



form. Generally there is not a single nucleolus of large size, but 

 several small ones. No chromatic network or granules have 

 been detected. There is no peripheral yolkless layer. In the 

 single specimen containing ova they are very numerous, appar- 

 ently nearly mature, and almost fill the ccelom of each somite. 

 It is thus evident that within the genus Lycastis there are species 

 differing widely in the structure of their ova. 



None of the sectioned specimens that I have examined have 

 ripe spermatozoa, but the sperm-cells (spermatocytes ?) present 

 are apparently all in the same advanced stage of development. 

 Unlike the ova, they occupy every somite from first to last of the 

 series in which they occur, but the clusters of sperm-cells, as 



