173 



the bulb. A few nuclei appear in the vicinity of the sperm duct. This 

 duct penetrates the bulb on its ectal side, and after makin.s^ a bold 

 curve within the bulb opens into the shallow invagination. The bulb 

 is covered by a thin sheet of peritoneal membrane beneath which lies 

 a thin layer of muscle tissue. This musculature does not penetrate 

 the bulb, nor is the bulb divided into separate parts as seems to be the 

 case in some species of this genus. 



Spermatheccc. — Two moderately developed spermathecae are pres- 

 ent in V. Each spermatheca (PI. XII, Fig. 53) is distinctly differ- 

 entiated into two regions, the duct and the ampulla. The duct is 

 about four times longer than the ampulla, and is covered throughout 

 its entire length with small glands which give it a tuberculate appear- 

 ance. The lumen is very fine and the walls of the duct are thick. There 

 seem to be a few additional unicellular glands at the ectal opening, 

 but they are small and not easily seen. The ectal opening is some- 

 what latero-ventral in position and occurs near IV/V. From this 

 point the duct extends, without contortions, in a dorso-meso-caudal 

 direction. Before reaching the digestive tract it merges into the am- 

 pulla. The ampulla is spherical, thin-walled, and unites with the lat- 

 eral surface of the digestive tract by means of a short duct-like ex- 

 tension. All of the specimens studied showed masses of sperm cells 

 in the globular ampulla. 



The Pexiai. Bulb as a Character in Ceassification 



Previous to 1905 the structure of the penial bulb had not been 

 critically examined and no attempt had been made to discover in it 

 characters of taxonomic importance. It had been seen and very briefly 

 described by some of the earlier workers (Vejdovsky, Michaelsen, et 

 al), but the finer details of structure were neglected. Asa conse- 

 quence scarcely any of the earlier publications on Bnchytrmdcu give 

 information, either in text or figures, which can be used in estimating 

 the taxonomic value of this organ. Eisen (05) made critical studies 

 of it in about fifty species, distributed among eight genera, and gave 

 descriptions and figures of the structure of the organ in each case. 

 Unfortunately these species were not evenly distributed among the 

 eight genera, since in two of them but one species each was examined, 

 and in another only two species. The most thoroughgoing examina- 

 tion was made in the genus Mcscnchytrccus, in which twenty species 

 were studied. The results of this extended study are given by Eisen 

 ('05, p. 6) as follows : 



"The present arrangement of the various genera is partly tenta- 

 tive. Until now the structure of the penial bulb has not been critic- 



