2 aENUS TESTACELLA. 



for the sliovteuiiig of the coiinectivcs and commissures and tendency of the 

 gangUonic centres to concentrate around tlie pharynx, tlie ossopliagus passing 

 between tlie cerebral and buccal ganglia, and the anterior aorta separating 

 the pedal and visceral centres. 



The Euthyiieures are hermaphrodite and inoperculate pulmoniferous 

 species, usually possessing a highly vascular, respiratory pallial chamber, 

 without ctcuidia, but exceptionally developing secondary branchifc in a few 

 genera that are reacquiring aqueous respiration. 



Sub-Okder STYLOMMATOPIIOllA A.Schmidt. 



(Pulinonifcra, Reeve ; Helicea, Von M.irtciis ; Gcophila, Binney). 



The Stylommatophora (o-tcA.os, a pillar ; o/x/iara, eyes ; <^epw, to bear), 

 embrace those Euthyneures with distinct head and two pairs of hollow 

 retractile tentacles, the posterior and longer pair are the ommatophores, 

 and beai- the eyes near their sunnnit, where is also Ljcated the chief seat of 

 the olfactory sense ; the smaller anterior pair are also olfactory, but more 

 especiall)' tactile, in function. The otocj^sts' are imbedded upon the pedal 

 ganglia and contain numerous otoconia ;■ the nerve centres are closely 

 aggregated 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.E Gray. 



(OleacinidEe, liiniiey ; Agnatha, Mcirch ; Vermivoia, Gray). 



The Testacellidn' embrace the genera Bhytida, Pnryphanta, Btreptaxis, 

 Dau<Ieh<trdi<i, GIkiiiHiik, and lV<f<iceJla, 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 

 Tc^t<(ri'Uii inhabits this country, but that Glandiim also formerly did so is 

 undeniably established by its fossil remains in our tertiary strata. 



(lENUs TESTACELLA Cuvier. 



(Helicolimax pars, Fi^r. ; Testacellus, Faure-Biguet). 



History. — Tc^facclU (dim. of testn, a shell) was discovered at Dieppe by 

 M. Duguc, and his careful and accurate observations on its habits and appear- 

 ance, under the appellation of "Limace i\ coquille," were published in 1740 

 by Reanmnr,^ who, however, did not apply to it any distinctive scien- 

 tific name. In ISOO, Cuvier, ■* impres.sed by the peculiarities of the shell, 

 created the genus TcntitrcUn for its reception, and in liS<U described and 

 figured the internal structure of the animal. 



Generic Characters. — E.xtehnally, the distinguishing features of 

 T(vf<(ri'lli< may be summarized as : Body limaciform, markedly attenuate 

 anteriorly ; integi'ment coriaceous, thickest in tlie roar; peripodial guoove" 

 distinct; tentatles simple, without definite apical enlargement; eyes small 

 and black'; Lii's tactile and very extensible; lateral grooves" distinct, 

 diverging from the peripallial sinus and terminating near the base of the 

 tent.-irles, giving olf from each side a number of supra- and sub-lateral, an- 

 teridvly directed, sliallow, l)ranchiiig grooves, whose intersections form the 

 granulation which is so manifest (luring cfintraclion ; SOLE not tripartite as 

 in LiiiiK.r-, mantle small, placed quite in the rear of the animal, and covered 

 by a vestigial^ and .somewhat, auriform, paucispiral shell, from which the 

 ]ii'ri(istracum is usually more or less abraded ; MUScuLAii SOAR cresceutic in 

 shape; HESPiRATOKY iind ANAL oiupicEs bcueatli right posterior angle of 

 shell. SexuaJ oriHc(U)ciieath right omniatophore. 



1 Monog. i. ,,. 2.17, n. 2 M„„oj. !., p. 2.30, fT, .■) OI,...r,-. de Physique cdilL^rale, pp. 1. 2. 

 4 Lci-ons d Anal. Lump. 1, 1, 5e tahl. o Monog. i., p. 11)2, r. 377. U Monog i., pr^Oo, f. 10-'. 



