HELIX. 315 



a manifestation of this group. In the upper Miocene, H. sylvana, 

 sylvestrina, etc., represent this group. In late Pliocene and Post- 

 Pliocene times, Tachea was represented by numerous forms, such as 

 sepulta Mich., tonnensis Sandb., and those described by Nevill from 

 Mentone. The section OTALA (Macularia Auct.) has a similar his- 

 tory, appearing at about the same time, in moderately characteristic 

 forms, many with the malleation of the recent species, as seen in 

 H. nayliesi, etc. HEMICYCLA, now confined to the Canary Islands, 

 seems to have had a wide range in the Miocene, some species, such 

 as asperula Dh. being excessively similar to recent forms. The iso- 

 lation of the Canaries has evidently preserved there this ancient 

 race. There are a number of Tertiary forms of Europe known to 

 me by figures or poorly preserved specimens only, which will event- 

 ually no doubt form new groups. 



If. doderleiniana All. of the Sicilian Pliocene seems to represent 

 a section distinct from Otala, although allied to that group, which 

 may be called Allolcemus. It is distinguished by the extraordinary 

 expansion of the last whorl toward the aperture, after a wide shal- 

 low constriction, causing the throat to be quite narrow, although the 

 mouth is expanded and the outer lip flaring. General form globose- 

 depressed. The specimen before me is from Palermo, collected by 

 Benoit. 



It has not been considered necessary to give varietal names to the 

 band variations of these five-banded Helices. They may better be 

 expressed by the well known formula originated by Martens pere 

 (Ueber die Ordnung der Bander an den Schalen mehrerer Land- 

 schnecken, 1832), and explained in the Introduction to this vol- 

 ume. 



Synopsis of sections and subgenera. 

 I. Penis provided with a flagellum. 



a. Baso-columellarlip straightened and widened by a callous plate 

 within. 



b. Imperforate, globose-conic, periphery round, smoothish ; 



usually yellow or white, banded Tachea*. 



bb. Imperforate, globose-depressed, periphery round, smooth 



or malleated, solid ; uniform, or speckled and banded 



Otala. 



bbb. Globose-depressed, malleated, ribbed or granulate, dark, 

 usually banded Hemicycla. 



