2 GENUS TESTACELLA. 
for the shortening of the connectives and commissures and tendency of the 
eanglionic centres to concentrate around the pharynx, the cesophagus passing 
between the cerebral and buceal ganglia, and the anterior aorta separating 
the pedal and visceral centres. 
The Euthyneures are hermaphrodite and inoperculate pulmoniferous 
species, usually possessing a highly vascvlar, respiratory pallial chamber, 
without ctenidia, but exceptionally developing secondary branchiz in a few 
genera that are reacquiring aqueous respiration. 
Sus-Orpver STYLOMMATOPHORA A. Schmidt. 
(Pulmonifera, Reeve ; Helicea, Von Martens ; Geophila, Binney). 
The Stylommatophora (o7tAos, a pillar; oppara, eyes: depo, to bear), 
embrace those Euthyneures with distinct head and two pairs of hollow 
retractile tentacles, the posterior and longer pair are the ommatophores, 
and bear the eyes near their summit, where is also located the chief seat of 
the olfactory sense ; the smaller anterior pair are also olfactory, but more 
especially tactile, in function. ‘The otocysts' are imbedded upon the pedal 
ganglia and contain numerous otoconia ;° the nerve centres are closely 
ageregated and fused together in a nerve ring around the pharynx, and 
the sexual orifices are closely contiguous or united in a common passage at 
the side of the neck. 
FAMILY TESTACELLID-X Gray. 
(Oleacinidz, Binney ; Agnatha, Mirch ; Vermivora, Gray). 
The Testacellidw embrace the genera Ithytida, Paryphanta, Streptavis, 
Daudebardia, Glandina, and Testacella, with a few other exotic groups, all 
characterized by an enormous development of their radula, by the absence 
of the mandible, and by their predacious habits. Of these genera only 
Testacella inhabits this country, but that Glandina also formerly did so is 
undeniably established by its fossil remains in our tertiary strata. 
GENUS TESTACELLA Cuvier. 
(Helicolimax pars, Fér. ; Testacellus, Faure-Biguet). 
History.—7vstacellu (dim. of testa, a shell) was discovered at Dieppe by 
M. Dugué, and his careful and accurate observations on its habits and appear- 
ance, under the appellation of “ Limace & coquille,’ were published in 1740 
by Reaumur,* who, however, did not apply to it any distinctive scien- 
tific name. In 1800, Cuvier,t impressed by the peculiarities of the shell, 
created the genus 7¢estucella for its reception, and in 1804 described and 
figured the internal structure of the animal. 
Generic Characters.—ExTerNALLy, the distinguishing features of 
Testacella may be summarized as: Bopy limaciform, markedly attenuate 
anteriorly ; INTEGUMENT coriaceous, thickest in the rear; PERIPODIAL GROOVE? 
distinct ; TENTACLES simple, without definite apical enlargement; EYES small 
and black; Lips tactile and very extensible ; LATERAL GROOVEs® distinct, 
diverging from the peripallial sinus and terminating near the base of the 
tentacles, giving off from each side a number of supra- and sub-lateral, an- 
teriorly directed, shallow, branching grooves, whose intersections form the 
granulation which is so manifest during contraction ; SOLE not tripartite as 
in Limae: MANTLE small, placed quite in the rear of the animal, and covered 
by a vestigial and somewhat auriform, paucispiral SHELL, from which the 
periostractin is usually more or less abraded ; MUSCULAR SCAR crescentic in 
shape; RESPIRATORY and ANAL ORIFICES beneath right posterior angle of 
shell. Sexual orifice beneath right ommatophore. 
1 Monog, i., p. 237, ff. 2 Monoz. i., p. 239, ff. 3 Observ. de Physique générale, pp. 1. 2. 
4 Lecons d’Anat. Comp. t. 1, de tabl. 3 Monog. i., p. 192, f. 377. 6 Monog i., p. 205, f. 402. 
