HYALINIA LUCIDA. Lg 
according to many conchologists be included; and judging from a type 
shell expressly selected for me by the late M. Bourguignat, the Zonites 
subglaber must also be considered as belonging to the present species, 
while Herr Julius Hazay records having received this species from the 
south of Russia under the name of /yalina diaphanella of Krynicki. 
BiGaozs BiGeoos Fic. 34. ENGuoos Fic. 36. 
Upper and basal aspects of certain Tyadinie assumed to be synonymous with //. /ucida (Drap.). 
Fic. 32.—Hyalinia antoniana Paulucci, Sardinia (after Paulucci). 
Fic. 33.—Hyadinia porroi Paulucci, Genoa (after Paulucci). 
Fic. 34.—Hyadlinia isseliana Paulucci, Lucca (after Paulucci). 
Fic. 33.—Hyalinia tropidophora Mabille, Bastia, Corsica (after Paulucci). 
Fic. 36.—Zonites subglaber Bourg., Morbihan (after Bourguignat). 
The sub-genus Huhyalinia embraces the larger species of Hyalinia with 
very glossy shells, and more numerous whorls than their allies of the 
related group Politu. 'The radula is characterized by a relatively small 
mid-tooth flanked by large and irregularly tricuspidate laterals and by the 
fewness of the teeth in each transverse row as well as on the membrane 
generally. ‘I'he vas deferens is peculiar in forming a distinctly looped stiff 
median enlargement, which may be the secretory lumen of the capreolus. 
Amongst themselves the species of the restricted group show a close 
affinity externally in shell and animal, and also present considerable 
general conformity in their internal organization, and it is evident that 
these forms have not yet diverged greatly from a common ancestral type. 
Diagnosis —The sueti of //. lucida may be known from any other of 
the more closely-alhied of our native species by its larger size, its more 
elevated and convex spire, and the rapid enlargement of the last whorl 
towards the aperture, which is perceptibly more oval and more obliquely 
placed in regard to the shell axis than in //. cellaria, its nearest ally. 
Immature shells approach much more closely to HA. cellaria, but with 
attention to the differential points can usually be correctly separated. 
From H. nitidula and its var. nitens it may be known by its larger size, 
narrower umbilicus, more glossy aspect, and by the lesser compression and 
dilatation of the last whorl. 
The ANIMAL is remarkable for its deep slaty-blue colour, which extends 
to the side-areas of the sole, and in a less degree to the locomotory mid- 
area as well as to the internal organs; this character separating the animal 
from that of 7. cellaria, in which the sole is usually quite pale. 
INTERNALLY, it may be distinguished by the marked obliquity in 
position of the compound abdominal ganglia, due to the extreme shorten- 
ing of the visceral commissure on the right side of the body ; by the shape 
and the characteristic twisting of the epiphallus, and by the constant 
presence on the lingual membrane of one well-marked lateral denticle more 
than on the radula of /7. cellaria, alliaria, helvetica, ete. 
