292 N. M. Stevens. 



dial nature of the 'besondere Korper' and of the nucleolus-hke 

 bodies of the oogonia and oocytes, I have spoken of in describing 

 the development of the oviduct. I find no such connection with 

 the 'accessory' cell as he figures on page 435, and a careful review 

 of all my preparations of material from four species has only served 

 to confirm my previous account of the appearance and function 

 of the two epithelial cells which connect each oocyte with the 

 sperm-duct. 



The Accessory Fertilization Cells 



Fig. 38 shows an exceptionally good section of the accessory or 

 connecting epithelial cells in Sagitta bipunctata. The fertilization 

 canal, which Buchner says he has not been able to find, is shown, 

 and the spermatozoon (s) is partly in the second cell. It is only 

 occasionally that one finds the spermatozoon in the cells, but when 

 found, it is not to be mistaken for any such connecting fiber as 

 Buchner figures. In the broad portion of the canal there is a large, 

 granular non-staining spindle-shaped body (6) which may, I think, 

 be some substance attractive to the spermatozoa. This I first saw 

 in living eggs while attempting to observe the entrance of a sper- 

 matozoon into the fertilization canal. In the living eggs both con- 

 necting cells can be distinguished, though their nuclei are invisi- 

 ble and the canal extending through both cells is plainly seen, 

 as is also the spindle-shaped body in the widest part of the 

 canal. Fig. 39 is a camera sketch from such a living egg of 

 Sagitta inflata, with the nucleus visible but near the periphery 

 of the egg, indicating the approach of maturation. Many sper- 

 matozoa were around the mouth of the canal, but I have never 

 been able to detect one in it, possibly because I have used too 

 late a stage for observation. 



Fig. 40 shows another case where a part of a spermatozoon is 

 seen in a section of the canal in the inner accessory cell. Figs. 41a 

 and h show the same cells from an egg of Sagitta minima. Here 

 the fertilization tube (c) is coiled in the outer cell. This I also 

 observed in the living egg. Fig. 42 is a section through these cells 

 in Sagitta elegans showing several portions of the more or less 



