•280 JOURNAL OF CONCHOLOOY, VOL. l6, NO. 9, JUNE, I922. 



divided his "Aplostomes." But in any case Herrmannsen's designa- 

 tion has priority over Gray's. 



It is true that the type given by Herrmannsen — H. ericetorum 

 Miill. — is placed by Ferussac among his " Heliomanes," and not 

 among his " Aplostomes " ; but there is no Rule which implies that 

 in order to be valid the type of Ferussac's subgenus Helicella must 

 necessarily be selected from among those species which he placed in 

 a section thought by him to be most nearly equivalent to the supposed 

 Helicella of another author, Lamarck. On the contrary, Article 30 

 {a,b,d/,g) clearly seems to imply that when there is no type by 

 "original designation" or " absolute tautonymy" any species which was 

 originally included without question under the generic name may be 

 selected as type by a subsequent author, and such designation is not 

 subject to change. Consequently, as Ferussac included without 

 question H. ericetorum among his species of Helicella, the subsequent 

 designation of that species as type cannot be rejected according to 

 the International Rules. Therefore the application by Pilsbry and " 

 others of the name Helicella Fer. to the genus containing H. ericetorum 

 Miill. seems to have been correct, and this name has priority over 

 Jacosta Gray, HelicopsisYxiz., Xerophila Held, etc. 



Helicopsis Fitz., and Candidula Kobelt. 



In their last paper Gude and Woodward have acknowledged that 

 the name Helicopsis Fitz. (1833) ought not to be used in a generic 

 sense, as they had suggested ; but it should also be pointed out that 

 this name ought not to be applied to the subgenus Candidula Kobelt 

 (1871), of which H. candidula Studer is the type, and to which the 

 common British species H. caperata and H. gigaxii belong. The 

 type of Helicopsis Fitz. is H striata Miill., and in this species the 

 reproductive system has a pair of dart-sacs and a pair of accessory 

 sacs. On the other hand, in H. candidula, caperata, gigaxii, etc. 

 there is only a single dart-sac. ■'^ This is an important difference, 

 similar to the chief distinction between Trichia and the subgenus of 

 Hygromia which Gude and Woodward have named Monachoides and 

 which Hesse regards as a distinct genus. " Indeed the reproductive 

 organs of H. striata seem to differ from those of H. candidula, 

 caperata, etc., much more than do those of H. virgata. It is there- 

 fore evident that the name Candidula Kobelt is not a synonym of 

 Helicopsis Fitz., but that Helicopsis and Candidula should be regarded 

 as distinct subgenera or sections of Helicella. 



It is true that Pilsbry, although he said that these groups would 

 probably have to be separated, did not separate them himself, because 



1 Schmidt : Abhandl. Nalurwiss. Vereines f. Sachsen u. Thiiiingen, vol. t, 1855, pL vi. 

 Boycott and Jackson : Journ. of Conch., vol. xiv, 1914, p. 168 ; etc. 



2 Archiv f. MoUuskenkunde, 1921, pp. 61 — 66. 



