PUPA. 



TESTA oblongo-cylindracea, crassiuscula, an- 

 fractibus plurimis, plerumque transversim 

 eostellatis, apertura elliptica, plerumque den- 

 tata, infra rotundata, peritremate continue, 

 reflexo. 



Apparently a distinct Genus of Jand shells, related to 

 Bulinus and Clausilia, Its species are numerous, and they 

 seem to be common to all climates. Several minute 

 species are found in Britain, and many are abundant in 

 Europe, but the larger species belong to tropical countries. 

 The name has been given from a general resemblance of 

 some of the species to the pupa of some insects. The 

 Pupae are easily distinguishable from the Clausilice by the 

 absence of the internal elastic appendage which is found 

 affixed to the columella in that Genus, from which also 

 it has its name. The fact of all the Clausiliae being reverse 

 shells cannot be regarded as a distinguishing character, 

 because some of the Pupae are usually reverse shells. 

 There is much diversity in general form among the nume- 

 rous species of the Genus Pupa, some being short and 

 thick and very obtuse at the apex, others being of an 

 oblong and somewhat cylindrical form, and others again 

 very much elongated and acuminated. The Pupae are for 

 the most rather thick shells, with numerous volutions, 

 which are often finely ribbed transversely ; the aperture 

 is generally elliptical, sometimes rather quadrate at the 

 upper part, and rounded anteriorly. Peritreme continuous. 



