122 LOUISE B. WALLACE. 



early part of June they consist mainly of spermatogonia. In 

 Philadelphia the breeding season occurs a week or two earlier 

 than it does in Massachusetts. Late in the fall the male spiders 

 are fewer in number than the female spiders owing to the fact 

 that they are more often overcome and eaten by their mates. 

 Most of the adult spiders perish at the approach of cold weather. 

 The testes are translucent, slightly convoluted tubular organs 

 and can be easily seen as they lie inbedded in the voluminous, 

 brown liver which in mature specimens occupies the greater part 

 of the abdominal cavity. In very young spiders, however, it is 

 often difficult to distinguish the testes from the whitish, tubular 

 spinning-glands lying beneath them. In Agalcna it is a com- 

 paratively simple matter to determine the sequence of stages in 

 the development of the germ cells as in cross-sections of the 

 testes the least mature cells are always at the periphery, and they 

 increase in maturity toward the lumen. Sometimes in a single 

 cross-section can be found spermatogonia, spermatocytes, sperma- 

 tids and mature spermatozoa. In the height of the breeding 

 season the lumen and the ducts are filled with quantities of ripe 

 spermatozoa and degenerating cells. As was first discovered by 

 Menge ('43), the male spider has the peculiar habit of spinning a 

 small, delicate web and depositing upon it a minute drop of 

 seminal fluid which is then taken up into the fine, coiled tubes of 

 the pedipalps preparatory to its introduction into the receptaculum 

 seminis of the female. This process can readily be observed if 

 spiders be kept in captivity during the breeding season and Mont- 

 gomery ('03) has given a detailed description of it in a number 

 of genera. By teasing out the contents of the storing-organs of 

 the pedipalps one can obtain an abundance of spermatozoa which 

 are sure to be mature. 



METHOD. 



The spiders were beheaded and the testes dissected out in the 

 killing fluid. This method renders easy their removal from the 

 body and insures rapidity of fixation. Among the various fixing 

 fluids used were Zenker's fluid, Gilson's mercuro-nitric, Gilson's 

 acetic alcohyl with sublimate, Hermann's fluid and Flemming's 

 fluid, strong solution. Flemming's fluid gave slightly better 

 results than Hermann's and both of these fluids gave vastly better 



