256 GEOMALACUS MACULOSUS. 
The LINGUAL MEMBRANE is about eight mill. long and two mill. wide, and is 
said by Heynemann to be composed of 240 slightly eurved transverse rows of 
denticles, each row composed of a median tooth and fifty-seven lateral and marginal 
teeth at each side. The median teeth are small and elearly unicuspid, though 
slightly shouldered ; the lateral teeth are all bicuspid, but the admedian teeth are 
noticeably larger than the median row, and the mesocone is well developed, there is, 
however, no distinction between the lateral and marginal series except that the 
ectocone present on the admedian teeth recedes in position and slightly diminishes 
in size in the succeeding teeth up to about the twentieth row, but in the marginal 
series the ectocone gradually grows in size and importance as the margin is 
approached, while the mesocone becomes almost correspondingly diminished, the 
outermost teeth showing a more embryonic character; Judged by the theory of 
meso-metamorphosis the tendeney of the teeth development is towards an uni- 
cuspidate dentition. 
Br 9 45 40 30 15 6 
S2 51 5 %. 
al l cy 0 
WY eA AL AAD ALA 
ANTM GG 
( VLV EVI WV A 
} 
l 
5 30 40 45 59 5 52 54 
Fic. 269.—Representative denticles from a transverse row of the teeth of Geomalacus maculosus, from 
Lough Caragh, Ireland ; from a preparation by Rev. Prof. H. M. Gwatkin. 
The formula of a Lough Caragh specimen is, according to Heynemann : 
Sp Se ply at 4 33 x 240 = 27,600. 
Reproduction and Development.—'he congress of this species has 
not been observed or described, but judging by its structure, it is, aceord- 
ing to Simroth, 
probably — similar 
to that of Limar 
maxvimus, the long 
protruding penes 
intertwining spir- 
ally together dur- 
ing the process, 
as in the latter 
species. ‘he sper- 
matozoids must 
possess a very 
persistent vitality 
or the animal be Fic. 270.—Cluster of eggs of Geomalacus maculosus, deposited in captivity 
capable of auto- (photo. by Mr. R. Welch). 
fecondation, as a specimen kept in solitary confinement for three years by 
Mr. ‘I. Rogers, from August 1875, to July 19th 1878, deposited batches 
of fertile eggs in August 1876, and in July and August of 1877. 
The eggs have been observed to be deposited during July and August, 
in clusters of eighteen to twenty-four, adherent by a mucous-film; they 
are very large im comparison with the size of the animal, but vary 
within certain limits, the largest are more elongate, being eight-and-half 
by four-and-quarter mill., while the smallest 
are more regularly oval, and are only six by SS 
four mill. All the eges when fresh are beauti- 
ful semitranslucent milky-white or opalescent, ltrs ee hat tense 9 
but some of the larger and more elongate ones  tinctness ‘of the longitudinal band- 
show a somewhat transparent area at the & ‘fer Scharff). 
smaller end. In a few days the opalescent lustre becomes lost, and the 
eges turn yellowtsh and afterwards brown. ‘The young appear to hatch in 
from six to eight weeks, at which period the spots are barely present, but 
the lateral bands are distinct and black, and the shield shows the lyre- 
