1898.] NATURAL SCIENCES OF PHILADELPHIA. 223 



been called the " epiphallus." In the other type, to which Avion, 

 Geomalacus, Prophysaon and Aphallarion belong, the penis has been 

 lost through degeneration, and the vas deferens enters the atrium 

 directly, its lower course being enlarged or modified in various ways 

 (PI. XIII, all figs.) as described above, into an epiphallus. 7 The epi- 

 phallus is not evertibie, has no retractor, and does not have the 

 function of a penis. In it the sperm is lodged in packets or " sperm- 

 atophores." These, in Hesperarion and Prophysaon, are oblong, 

 narrow capsules of chitinous texture, with a loug, slender filament 

 at one end (PI. XII, fig. 43). They may occasionally be found in 

 the spermatheca (PI. XII, fig. 48, where the outlines of several are 

 faintly visible through the wall). In genera with this type of geni- 

 talia the vagina and lower portion of the free oviduct are introvert- 

 ible, and assume the function of the penis, being provided with a 

 retractor or retractors; and in some genera, such as A Hon, the 

 spermatheca duct also has a retractor muscle. In forms having the 

 spermatheca duct inserted directly upon the atrium, there is, of 

 course, no vagina, and the free lower portion of oviduct alone acts 

 as penis. 8 The peculiar enlargement of the epiphallus in Prophy- 



7 The term epiphallus was originally proposed some years ago by the senior 

 author of this paper for the structure as commonly found in such Hclicidte as 

 the West Indian Caracolus and Pleurodonte species, and in most of the larger 

 East Indian and Australian forms, in which it occurs associated with a well- 

 developed penis, as in Hesperarion, etc. It is strictly synonymous with Sim- 

 roth's term "Patronenstrecke." Mr. Collinge (Proc. Zool Soc. Lond., 1897, 

 p. 447) proposes to substitute "sperm-duct" for what we term epiphallus, 

 and restrict the latter name to '' the terminal portion of the vas deferens above 

 the sperm-duct." There is, of course, no objection to the substitution of an 

 English name for the Greek compound, but since the term epiphallus has 

 already been used in extensive and numerous works in America, England and 

 Germany, it seems a little revolutionary to completely alter its significance. 

 If Mr. Collinge wants a term for the vas deferens above the epiphallus, he 

 had better, to avoid confusion, invent a new one ; though what he wants it for 

 is not quite apparent. 



8 Arion is a case in point, cf. Collinge, Proc. Zool. Soc. Lond., 1897, p. 447. 

 Geomalacus also is similar. In Prophysaon and Aphallarion however, it is the 

 vagina proper which performs both its usual function and that of an evertibie 

 penis. We consider Mr. Collinge's statement (/. c. ) that ''Messrs. Pilsbry 

 and Vanatta have suggested the term * * * vagina for what I term free- 

 oviduct " as an inadequate representation of our position, due, no doubt, to our 

 inadvertent enumeration of Arion as one of the genera in which the vagina 

 functions as a penis. We use the term "vagina" for the passage below the 

 union of the spermatheca duct with the free oviduct proper (see PI. XIII, fig. 

 57, vag. ), considering such usage justified by its functions. The term " free 

 oviduct" will naturally be retained for the passage from the apex of the va- 

 gina (when present) to the point of approximation of the vas deferens. Mor- 

 phologically, the vagina may be regarded as an elongated portion of the 

 atrium. 



