1892.] NATURAL SCIENCES OF PHILADELPHIA. 389 



slender continuation of the penis backward, extending to the inser- 

 tion of the vas-deferens, and usually continuing beyond this inser- 

 tion as a flagellum. The retractor is sometimes situated upon the 

 epiphallus instead of at the apex of the penis itself, this arrange- 

 ment being shown in the figure here given. (4) 1\xq flagellum (fl.) 

 a whip-lash shaped organ inserted upon either the summit of the 

 penis or upon the epiphallus. The female system consists of the 

 vagina (v.), which bifurcates to form the spermatheca or receptami- 

 lum seminis (sp.), and the uterus, a sacculated organ often containing 

 eggs or young in various states of development. Surmounting the 

 uterus is the albumen secreting gland, at the base of which the 

 hermaphrodite duct enters the oviduct and vas-deferens. Besides the 

 organs above described, the female system in some groups possesses 

 a dart sack or sacks secreting a dart, and one or two mucous glands, 

 these organs being inserted upon the vagina. Another organ of 

 rai'e occurrence is the appendicula, an elongated simple diverticulum 

 also emptying into the vagina. This diverticulum is supposed by 

 V. Ihering to be homologous with the appendix of the male system ; 

 and it is certainly strong evidence of the correctness of his view 

 that no form yet known possesses both appendix and apj^endicula. 

 It is further held by him that the dart sack in Zouitidce is the 

 homologue of the appendix ; but this theory requires before adop- 

 tion much stronger evidence than has been given. 



From the foregoing it will be seen that the following points should 

 be carefully observed when dissecting the genitalia of Helices: 

 Shape of the penis and presence or absence of internal papilla and 

 external appendix ; presence or absence of flagellum or epiphallus ; 

 point of insertion of the retractor muscle and of the vas deferens. 

 Upon the female system should be noticed the absence or presence 

 and form of dart sacks, darts, mucous glands or appendicula ; the 

 length of the spermatheca duct ; the form of the cceca of the ovo- 

 testis and whether they are imbedded in the liver or free; and 

 finally whether the right eye-peduncle is retracted between the 

 branches of the genitalia or to the left side. 



The flagellum, the dart sack and accompanying mucous glands, 

 and the diverticulum upon the spermatheca duct may be regarded as 

 structures developed since the differentiation of the Helices from 

 other stocks ; but the appendix and probably the appendicula, when 

 present, have been inherited from that primordial stock from which 

 the Helicidre, Pupidte, Bulimi etc. have diverged. As is sometimes 



