THE SPERMATHECA OF EURYCEA BISLINEATA. 257 



which is intermediate between the young and the mature sperma- 

 theca. This was a 71 mm. female caught and killed in September. 



In this spermatheca the average number of tubules found in a 

 mature organ is not complete (though at least one functional 

 organ in this study was observed with no more) and only one 

 pair, one tubule on each side of the median line, is mature in 

 size and cell structure. The necks of these two largest tubules 

 are well developed: the lumina appear at first sight to be open 

 but upon higher magnification they are seen to be so filled with 

 the faintly stained apices of the columnar cells as to be virtually 

 closed tubes. The remainder of the tubules and their necks are 

 in various stages of development. 



A most marked development of the central tubule is evident. 

 This seems much out of proportion to the same duct in the fully 

 mature organ. The extent is less, that is, the tube is short and 

 does not extend far posterior, but the diameter is wide. Above 

 the short, stout entrance the duct immediately widens into a 

 very broad chamber into which the necks empty. Most of the 

 necks being rather immature their confluence is not so graceful 

 as is typical in older spermathecae. Also the cells of the columnar 

 lining of the central tubule have not the length and delicacy of 

 apices peculiar to this duct in all later stages, and consequently 

 they are not so conspicuous. 



Lastly pigment is present in quantities but not in the arrange- 

 ment of the mature organ. Sockets around the ends of the two 

 largest tubules are being formed. Around some of the smaller 

 tubules also it has gathered in tangled networks, but around the 

 largest pair it is more concentrated coarse, thick strands. 

 Aside from these foci the pigment is scattered and the pigment 

 producing cells still visible. The definitely bounding walls of 

 the organ are not formed. 



The spermatheca just described measures slightly less than 

 1/3 mm. in length and must suffice to complete the develop- 

 mental series. But a word may be said about the largest 

 spermatheca observed during this investigation. The animal 

 was a 95 mm. female killed in September. Unfortunately for 

 the series as a whole it was sectioned horizontally but the sperma- 

 theca is perfect. Eighteen tubules were counted and, although 



