CLASSES, ORDERS, ETC. 77 



vertical line. The vas deferens enters the penis "terminally 

 in T. scutulum and maugei : laterally in T. haliotidea ". Gardens 

 and fields. Local. T. scutulum. 



(c) Shell resembling that of T. haliotidea, but larger and more 

 cylindrical. Body dark brown. Gardens and fields round 

 Bristol. T. maugei. 



Family IV. Helicidae. 



Shell spiral. Body distinct from the foot, tentacles four, re- 

 tractile, cylindrical, the upper pair being the longest and bearing 

 the eyes at their apices. 



20. Succinea. Shell oval or oblong, thin, transparent; spire 

 short ; mouth large and obliquely oval ; non-operculated. Animal 

 not capable of entirely entering its shell. 



(a) Shell ovate, oblong, smooth, glossy, amber-coloured, trans- 



Fig. ^.--Succinea putris. 



parent ; whorls three to four, ventricose, the body whorl occupying 

 fjths the length of the shell ; mouth ovate, two-thirds the length of the 

 shell. Length \ to f ths inch. On the banks of ditches and streams 

 on flags and willows. Moderately common. S. putris.^ 



(b) Shell amber-coloured, semi-transparent; compared with that of 

 S. putris it is smaller, more slender, with a longer and more pointed 

 spire ; the suture near the mouth is also much deeper. Length \ inch. 

 Marshes and ditch banks. Moderately common. S. elegant.* 



(c] Shell oval, elongated, pale yellow or reddish, transparent ; 

 whorls three, twisted, the body-whorl occupying near the whole 

 of the shell ; spire short, with the apex tuberculous ; suture oblique, 



48 v. subglobosa, shorter, broader, smaller, more solid ; v. solidula, reddish- 

 yellow, much thicker ; v. ferussina, deep reddish-fawn coloured, small, 

 slightly elongated ; v. vitrea, shell oblong, suboval, thin, greenish-yellow, 

 transparent ; spire very short ; mantle ovate. 



49 v. albida, white ; v. minor, thinner, reddish-brown, spire shorter, aperture 

 more expanded ; v. ochracea, thicker, smaller, spire longer, aperture smaller. 



