218 FERUSSACIA. 



franchian stage, belonging to the folliculus group. See Sacco, 

 I Moll, terreni Terziarii del Piemonte etc., pi. 22, p. 75, pi. 6. 

 Ferussacia insignis Babor, Sitzungsber. k. boehm. Ges. der 

 Wissensch. 1897, II, Art. 63, p. 8, fig. 3, Miocene, Tuchoritz, 

 is apparently a precursor of the folliculus group. 



Subgenera and Sections of Ferussacia. 



Subgenus FERUSSACIA. 



Section Ferussacia s. str., Mediterranean region. 



Species 1 to 15. 

 Mauritian species, no. 16. 

 Canary Is. species, no. 17 to 21. 

 Section Pegea Risso. Northern Africa, 1 in Italy. 



Species 22 to 62. 

 Subgenus AMPHORLLA Lowe. Madeira. Species 63 to 71. 



Sections Fusillus and Hypselia. 

 Subgenus PYRGELLA Lowe. Madeira. Species 72. 

 Subgenus CYLICHNIDIA Lowe. Madeira. Species 73, 74. 



Section Ferussacia Risso, s. str. 



Ferussacia Risso, Hist. Nat. Eur. Merid. iv, p. 80, for 

 F. gronoviana (figured) and F. sayea (undeterminable). 

 Vediantius Risso, Hist., p. 81, for V. eristaUus Risso (young 

 of F. gronoviana}. Pseudostreptostyla NEVILL, P. Z. S. 1880, 

 p. 665, for F. abnormis Nevill (young of F. vescoil) Folli- 

 culiana BGT., Rev. et Mag. de Zool. 1864, p. 201. Folliculina 

 Bgt., WESTERLUND, Fauna der in der Palaarctiseheii Region 

 lebenden Binnenconchylien, iii, p. 154 (1887). "Folliculus 

 Ag.," WESTERLUND, I. c., not of Agassiz. 



Shell oblong or cylindric oblong with convexly conic spire ; 

 aperture piriform, without a parietal lamella, the columella 

 with a single convex subvertical fold, not distinctly truncate 

 at base; outer lip thickened within, slightly retracted above 

 and below. 



This group consists of a large number of very closely re- 

 lated species or races and many local forms, spread over both 

 coasts of the Mediterranean from Greece to Portugal and 

 Morocco, but most numerous in northern Africa, Tunis to 



