LIMNiEIDi®. 
161 
LiMNiEIDiE. 
H. DE Lacaze-Duthiers distinguishes several lobes of differ- 
ent signification in the cerebroid or postoesopliageal ganglion : — 
first, behind, a lobe destined for the optic, acoustic, and olfactory 
nerves ; then, in front, a lobe for the issue of the connecting 
string going to the stomatogastric and penine ganglions, and 
another for the labial and penine nerves. The pedal ganglions 
give issue to three pairs of nerves, destined chiefly for the loco- 
motive organs, the columellar muscle, the muscles of the foot, 
and also for the part of the body behind the head which is ex- 
serted when the animal is creeping. Anotlier nervous centre, 
the inferior or asymmetric ganglion, provides for the mantle 
and all parts of the body sharing in the tension of the whorls ; 
and the greater size of one of the ganglions of this centre (the 
2nd left or the 2nd right) decides the direction of the whorls. 
[It may be questionable whether the unequal size of the gan- 
glions be the cause or ratlicr tlic consequence of the dcxtral or 
sinisfcral twisting of tlic mantle and shell.] There is a peculiar 
nervous organ, probably of a special sense, near the respiratory 
orifice, formed by the pallial postvulvar nerve, in which a part 
of the external skin and the cylindrical epithelium from the 
outside of the body is, as it were, invaginated into the midst of 
a nervous ganglion : this invagination is simple in the sinistral 
genera {Physa and Planorbis), and double in the dextral 
(Limrt^a). The observations are made on Limncea stngnalis, 
nnriculariaj and^^erc^'m, Physa fontinolisy and Planorbis corneus. 
Arch. Z. Par. i. pp. 437-501, pis. 17-20, 
Limncoa tumida (Held), from Lake Starnberg, Southern Bavaria, dis- 
tinguished as a species from auricularia (L.) : S. Clessin, Mai. Blatt. xix. 
p. 113. 
L. lagotis, var. n. solidisswia, Kobelt, ihid. p. 77, pi. 2. figs. 17 & 18, Himalaya. 
L. traski (Tryon) from Alaslta, Martens, ibid. p. 79. 
TAmncra pfdimri, sp. n., Dali, Am. J. Conch, vii. p. 135, Taqui Biver, 
Northern Mexico. 
Physa tcmrifccy sp. n. (with varr. fncrtcvcnturccy palmcnsisy gomcranay and 
gramanaricB)y and veniricosa (Moq. Tand., as var. of acuta)^ sp. n., from the 
Canaries, distinguished from the European acuta (Drap,), by Mousson, Ma- 
lacol. Can. pp. 137-139. 
Physa, a somewhat aberrant form of jaw and radula, in an undetermined 
species, from Guadeloupe, is described by Bland & Binney, Ann. Lyc. N. 
York, X. pp. 255 & 256, pi. 11. fig. 9. 
Glyptophysa, g. n., like Physa, but the shell spirally sculptured and not 
glossy. G. peiiti, sp. n., Crosse, J. de Conch, xx. p. 71 (as Physa) and pp. 161- 
153, New Caledonia, and Physa alicim (Beeve), Australia. 
Amphipeplea glutinosa appears chiefly in March and April : Nyst, Bull. Mai. 
Belg. vii. p. liii, and Maltzan, Arch. Ver. Mecklenb. xxvi. p. 82. 
Planorbis. 13 species of this genus, observed in Bavaria, south of the 
