210 



While working with a series of sections of a male pinnule of A. 

 rosacea'' I noticed a number of pores penetrating nearly through the 

 wall, which upon further examination were found to be present in a 

 number of pinnules upon each arm of the two specimens examined. 

 As many as four pores were found on a single pinnule, they having, 

 however, no very definite position other thvan being in the neighbor- 

 hood of the sacculi. From the specimens examined I am led to believe 

 that these pores are present in ripe pinnules and that through them 

 the spermatozoa are expelled. 



Fig. 1, a longitudinal section of part of a ripe male pinnule, shows 

 one of the pores and its relation to the other parts of the pinnule. The 

 regularity of the infolding of the germinal epithelium is at certain 



Fio-. 1. 



Fi-. 2. 



G-e.t 



Fig. 1. Longitudinal section of part of a male pinnule. Sp, spermatozoa; Gep, ger- 

 minal epithelium; top, wall of pinnule; Gp, genital-pore; Sc, sacculus. Zeiss, Obj. 



A. Oc. 2. 



Fig. 2. Section of a genital-pore filled with spermatozoa. Sp, spermatozoa; wp, wall 



of pinnule. Zeiss, Obj. D. Oc. 2. 



points interrupted; here the genital strand has grown towards and 

 partially through the wall of the pinnule, and the lining epithelial cells 

 show much plainer at this point than in any other part of the section. 

 The fully developed and developing spermatozoa show a longitudinal 

 linear arangement which is broken wherever one of the genital pores 

 is developed and at this point they pass outward to fill the pore, un- 

 doubtedly remaining within it until its rupture, when they are expelled 

 into the water. 



In Fig. 2, a more highly magnified view of another pore, the 

 epithelial cells of the genital strand are shown pushed nearly through 

 the wall of the pinnule. The nuclei of both the genital epithelium and 

 the wall of pinnule were easily seen, but I was unable to distinguish 



6 My material was taken from museum specimens prepared at the Zoological. 

 Station in Naples. 



