114 THE NAUTILUS. 



uable information in regard to several of Bourguignat's types, which 

 have enabled me to definitely determine the species described by that 

 author. 



The distribution of the AncyUdae in North Africa is entirely in 

 in accord with the faunal limits set forth by Germain in his recent 

 essay on the "Malacographie de L'Afrique Equatorial", (1909, p. 

 118). According to that author Africa, north of Lat. 11 N. and 

 including the Azores, the Madeira, Canary and Cape Verde Islands, 

 belongs to the Palsearctic Region. In the fluviatile Mollusca, how- 

 ever, the Valley of the Nile forms an exception and is populated by 

 the characteristic fauna of the Equatorial Region. And this is true, 

 also, in regard to the Ancylidce. 



In Europe, Ancylus is represented by two, and only two, very dis- 

 tinct groups: Ancylus s. s., of which A. fluviatilis L. is the type, and 

 Acroloxus, of which the type and only species is the A. lacustris L. 



The latter does not seem to have extended its range across the 

 Mediterranean. But thefluviatilis group is found in great abundance 

 and variety from Abyssinia to Morocco. 



Two species have been described from Abyssinia by Jickeli, (1874, 

 p. 223), A. abyssinicus and compressus,for the latter of which Bour- 

 guignat, (1883, p. 84), has proposed to substitute the name of hama- 

 cenicus, compressus being preoccupied both by Parreyss and Nyst. 

 Clessin, (1882, p. 31), considers it to be only a variety of abyssinicus. 



The collection of M. Pallary contains one species from Tunis. 



Thirteen species of more or less doubtful validity have been listed 

 from Algeria by Bourguignat and others. 



Four species are listed from Morocco by Pallary in his last cata- 

 logue (1904, p. 54.), of the fauna of that country. 



The A. aduncus Gld. from Madeira is referred to the European 

 A. striatus Q. & G. by Wollaston, (1878, p. 470). 



According to that author tiie same species, striatus, occurs abun- 

 dantly on the islands of Grand Canary, Pal ma and Teneriffe in the 

 Canaries. 



The A. rupicola Mouss. (1872, p. 141), from Teneriffe is an allied 

 and probably depaupei'ate form of the same species according to 

 Wollaslon. 



All of these species undoubtedly belong to the group of A. fluviatilis 

 and show that the ancyloid fauna of these countries is purely palas- 

 arctic. 



