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oe MONOGRAPH OF BRITISH LAND AND FRESHWATER MOLLUSCA. 
Genus VITRINA Draparnaud. 
(Vitrinus, Montfort ; Cobresia, Hiibner ; Hyalina, Studer ; Limacina, Hartmann ; 
Helicolimax, Férussac; Semilimax, Férussac; Pagana, Gistel). 
ISTORY.— Vitrina (vitrum, glass) 
was first satisfactorily differentiated 
and named by Draparnaud, in 1801, and 
its members have since been subdivided 
into several sections by later authors 
under the names of Semlimax Stabile, 
Chlamydea Westerlund, Phenacolimax 
Stabile, Oligolimax Fischer, ete. 
A family Vitrinidw is not adopted, as 
tending to unduly enhance the import- 
ance of the small group of species which 
should rightfully be referred to it. As 
usually employed, the family Vitrinide 
embraces a somewhat heterogeneous 
assemblage of genera, whose only point 
of resemblance is that the constituent 
species are passing through a similar 
stage of shell deterioration, and there- 
fore exhibit externally a superficial 
similarity to each other, though far 
removed in structural characters. 
Vie 7 Our British species is referable to the 
croup Phenacolimaz, while V. diaphanu 
which represents the section Semilimax, 
is said by Dr. Jeffreys to have been 
found in the Upper Tertiary strata of 
this country, but this record is inherently improbable, and is more likely 
to be a result of an error of identification. 
The genus Vitrina is associated with the gifted conchologist and 
paleontologist, Prof. Spiridon Brusina, Chancellor of the University of 
Agram, Croatia, whose numerous and esteemed works have contributed so 
largely to the elucidation of the conchology of South-eastern Europe. 
Generic Characteristics.—ExTEeRNALLY, Vitrina has an elongate 
Bopy, capable of a more or less complete retraction within the shell; on 
the dorsal surface there is a rudimentary SHIELD, upon which are found 
the pallial grooves so characteristic of Milar, the shield also partially 
envelops the shell and is prolonged laterally as a spatuliform lobe ; the Foor 
is rather narrow and indistinctly tripartite; RESPIRATORY ORIFICE on the 
right-side of the body and on the margin of the shield; REPRODUCTIVE 
ORIFICE also dextral, but placed near the middle of the neck. 
The SHELL, which in this group is undergoing a process of degeneration 
leading towards its eventual loss, is more or less imperforate, paucispiral, 
sub-globular in shape, very thin and pellucid, aperture auriform and ample, 
hip thin and sharp, but with the lower margin becoming broadly and 
simply membranous in the more advanced species inhabiting the active 
evolutionary area of Europe. 
