HELIX. 207 



is only a variety of H. nemoralis and allied to the one 

 called hybrida, there does not appear to be any greater 

 reason for changing Montagu's name than there was in 

 the similar case of H. revelata. 



D. Shell subcorneal or depressed, and banded : outer lip streng- 

 thened by an internal rib : umbilicus large or distinct. 



15. H. Pisa'na^ Miiller. 



H. Pisana, Mull. Verm. Hist. pt. ii. p. 60 ; F. & H. iv. p. 56, pi. cxv. f. 7, 8. 



Body yellowish-grey with a tinge of red in front, rather 

 strongly tubercled : mantle often dark-brown, tinged with 

 yellow and marked with very small and numerous milk-white 

 specks : tentacles rather broad at their base, but slender, finely 

 shagreened; the so-called optic nerves continue along the 

 neck, so as to form two dark lines ; bulbs very globular and of 

 a reddish colour, indistinctly speckled with brown : foot long, 

 somewhat truncate in front, gradually narrowing and pointed 

 behind, but not keeled. 



Shell subglobular, slightly compressed above, convex below, 

 rather solid and opaque, moderately glossy, yellowish-white, 

 beautifully marked with brown spiral bands, which vary greatly 

 in number (there being sometimes as many as fifteen or sixteen 

 on the last whorl, but usually only one underneath), and more 

 or less marked transversely with short oblique streaks of the 

 same colour, causing the upper part of the shell to appear 

 speckled ; sculpture consisting of irregular striae in the hne of 

 growth and of fine, close, spiral striae, which intersect the 

 transverse striae on the upper whorls and give to the smf ace a 

 delicately reticulated appearance : periphery rounded : epi- 

 dermis extremely thin and only perceptible under a micro- 

 scope : whorls 5|, very convex but compressed towards the 

 suture, the last occupying considerably more than one-half of 

 the shell : sjyire somewhat raised, but having a blunt point, 

 which is of a purplish-brown colour : suture rather slight : 

 mouth forming a segment of two-thirds of a circle ; interior 

 sometimes pink or blush-colour and fmnished with a slight 

 rib, which is either pale yellowish, white, or pink : outer lip 

 sharp, but thickened, reflected in the direction of the umbilicus 



* First fouud at Pisa. 



