Il6 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



to unite to form commissures, but sections and injections^ 

 clearly show that such is not the case. 



The cells lining the intestine are cubical or rectangular in 

 outline in individuals which have been kept for some time 

 in captivity. In an active condition their free borders 

 become irregular and amoeboid in appearance, and in very 

 many cases seem to be in the act of liberating portions of 

 their substance. This makes it altogether possible that they 

 are zymogenic, producing some ferment which acts upon 

 the food ; but there is no definite proof that such is actually 

 the case. 



The food of this trematode consists of the slime from 

 the surface of the body of the host. In rare cases this in 

 an apparently unchanged condition may fill the cavity of 

 the intestine, but in most cases it rapidly dissolves after its 

 entrance into the body. In living individuals the resulting 

 watery food substances, containing numerous granules, may 

 be seen to circulate backward and forward owing to the 

 periodical dilation and contraction of the intestinal walls. 

 The indigestible substances, chalky white in appearance, 

 and somewhat viscous, gradually accumulate in the tract 

 immediately behind the oesophagus, and are finally violently 

 expelled. 



IV. The Male Reproductive System. 



In E^idella squamula, as in all monpgenetic trematodes, 

 the male and female reproductive organs occur in the same 

 individual. The testes (fig. 11, /), two in number, are 

 more or less round disc-shaped bodies situated about the 

 middle of the animal, equidistant from the dorsal and ven- 

 tral surfaces. Each is surrounded by a feltwork of deli- 

 cate fibers of connective tissue which extend to it from the 

 neighboring parenchyma, and is penetrated by several bun- 

 dles of dorsoventral muscle fibers which pierce the sheath. 



1 Injections of the alimentary canal, and often of many of the branches of the excretory 

 system, may be made by transferring the specimens from absolute alcohol directly into 

 a clearing agent, such as oil of cedar or cloves. Owing to the inequality of the osmotic 

 currents, these tubes under favorable circumstances become completely filled with air. 



