™, 
22 HYALINIA LUCIDA. 
truncated mesocone as so frequently found in H. helvetica; the true laterals are 
three in number, and much larger than the median tooth, and usually bear three 
irregular cusps each, although the ectocone is frequently deficient on the outer 
denticle ; the fourth tooth is transitional, and has lost all traces of the ectocone, 
but frequently retains the endocone, which is occasionally apparently bifid, this 
appearance, however, according to Messrs. Moss and Boycott, being probably due 
to optical illusion ; beyond are ten strictly aculeate marginals, which decrease 
rapidly in size as they approach the margin. 
Some continental authors have described the radula as possessing but two 
3-pointed lateral teeth, as in H. cellaria, while others credit the species with 
possessing four characteristic tricuspid laterals ; but the bulk of British specimens 
have three characteristic laterals and one transition tooth on each side. 
NAR AOQ AL 
Fic. 45.—Transverse row of teeth from the odontophore of AHyadinia lucida, x 80. The animal 
collected by Mr. F. G. Fenn at Isleworth, Middlesex, and the teeth prepared by Mr. J. W. Neville. 
The formula of an Isleworth specimen is 
: 5) OWNme Ors, 
AO 4543 4 04 341 4 10 x 30 = 870. 
Reproduction and Development.—Nothing is known relative to 
the congress of this species, except that the seminal element is transferred 
by means of a spermatophore, which Dubrueil expressly 
declares is secreted in the enlarged section of the vas fr * 
deferens. ‘The eggs are described as globose in shape, so 
one mill. to one-and-half mill. in diameter, of a dull or 
only slightly nacreous white, due to the somewhat cretace- fi. t7pperme 
ous envelope; they are laid singly, and not in clusters, 6 (after a_ photo. 
‘ i Se eee > nate oh : by Mr. W. Moss). 
to the number of thirty to fifty, during a period extend- 
ing from March to September; they hatch in about fifteen days, and 
become adult in the first months of their second year. 
Food and Habits.—//. lucida isa somewhat gregarious species, often 
living in colonies, and seldom found solitary or isolated. They are strictly 
geophilous, and according to some authorities quite subterranean in habit ; 
they never climb trees, preferring moist and shady places in gardens, 
woods, etc., generally concealing themselves during the day and in dry 
weather under stones, in the crevices of walls and beneath tufted plants, or 
among humid moss and debris, crawling away almost instantly in search of 
shade if placed in the sun. When erawling the shell is usually carried 
leaning to the left side, and towards the rear, but is occasionally borne 
sloping strongly to the right, while according to Draparnaud the ommato- 
phores are alternately extended during progression. ‘lhe heart has been 
observed to pulsate forty times per minute at a temperature of 62° Fahr., 
when the animal was in repose, the contractions increasing to fifty-four 
when in motion; while at 64° Fahr. it attains a speed of forty-five beats 
in the same space of time. 
Though in captivity feeding readily and thriving upon cabbage (Brassica 
oleracea), coltsfoot (Tussilago farfura), aud dock (Rumea obtusifolia), yet 
they prefer animal food when obtainable, and this preference is probably 
indicated by the preponderance of aculeate teeth upon the radula. A 
number of this species bred in captivity by Miss F. M. Hele, and fed upon 
chopped beef during the winter months, when green food was unobtainable, 
actually devoured the weaker members of the colony when the supply of 
ineat was discontinued. 
