THE NAUTILUS. 125 



That Bourguignat also included A.fluviatilis and other members of 

 Ancylus proper in Ancylastrum is unfortunate, but it does not invali- 

 date the genus." 



If Ancylastrum, Acroloxus, Ferrissia, etc., are retained as sub- 

 genera or sections of Ancylus, then the group of Jluviatilis would be- 

 long to Ancylus s. s. If, however, these other groups are to be con- 

 sidered, as they should be, of generic value, then there is no occasion 

 for any subgeneric or sectional designation of the fluviatilis group 

 at all. 



In addition to the various representatives of thefluviatilis group 

 represented in the fauna of Northern Africa as hereinbefore men- 

 tioned from Abyssinia, Tunis, Algeria, Morocco and the Canary and 

 Madeira Islands, the examination of the Pallary collection has re- 

 vealed the existence of the following species belonging to Ferrissia 

 and Gundlachia. 



FERRISSIA PLATYRHYNCHUS n. sp. PI. VII, figs. 1-3. 



Shell rather elevated, oval, the left margin somewhat more curved 

 than the right, anterior and posterior margins regularly rounded, 

 thin, translucent, light corneous, lines of growth regular and rather 

 strong ; anterior slope somewhat radially wrinkled ; apex large and 

 very prominent, radially striate, turned to the right and overhanging 

 the posterior slope, surrounded by a distinct constriction, which is 

 deeper posteriorly, obliquely flattened above, with an enormous api- 

 cal depression, surrounded by a strong ridge, which is more con- 

 spicuous along the posterior margin ; anterior slope convex ; posterior 

 slope very oblique and nearly straight below the apical constriction; 

 sides compressed ; lateral slopes flattened, oblique and nearly straight 

 on both sides. 



Length 3.75, width 2.25, alt. 1.25 mm. 



Type locality, " Baraki, pres le Gue de Constantine, Algeria." 

 Type in the collection of Paul Pallary. 



The occurrence of a species of Ferrissia in Algeria was a great 

 surprise. A recent visit to Geneva enabled me to examine the col- 

 lection of Bourguignat and I was able to satisfy myself that there are 

 no Ferrissias from Algeria in his collection. In view of the very 

 considerable amount of collecting that has been done in Algeria in 

 years past, the form here described would seem to be very rare as it 

 has not been found by any other collector and only a single specimen 



