280 Rev. R. T. Lowe on the genera 
Art. XXXIX. On the Genera Melampus, Pedipes und 
Truncatella: with Experiments tending to demonstrate 
the real nature of the Respiratory Organs in these Mol- 
lusca. By the Rev. R.T. Lows, B.A. 
Class. GASTEROPODA. 
Order. PECTINIBRANCHIA. 
Fam. Piicace®, (Les Plicacées, Lam., excl. Tornatella.) 
Gen. Mexampus, Wontf.; Les Melampes, Cuv.; Conovulus, 
Lam.; Auricule pars, Ejusd., Syst., et Féruss.; Volute species, Linn., 
Montag., Donov., Turt. 
Tentacula (2 contractilia) annulata, subcylindrica, obtusa, basi dis- 
tincta; oculis sessilibus, paullé supra basis angulum internum positis. 
Caput infra tentacula porrectum, sc. ante eorum basin deorsum spectans ; 
buccis labialibus utrinque magnis, dilatatis, anticé coalitis, depressis, 
horizontalibus, discum latum, bilobum, quasi pedis partem anticam, for- 
mantibus. Os subtus ad emarginationem in medio disci hujusce labialis ; 
simplex (ut in Helice,) sc. maxilla cornea, lunatd, supcriore; inferiore 
nulla. Pes simplex brevis ovalis anticé obtusissimus, vix truncatus ; 
posticé subattenuatus, obtusus. Pallium collare (Je Collier, Feruss.) 
tumidum, siphone nullo ; orificio respirationis vel ani postico ad dextrum 
corporis, ut in Helice. Operculum nullum. 
Testa solida, subconiformis, laevigata, plerumque non sculpta, unicolor, 
vel spiraliter obscuré subfasciata. Spira breviuscula. Columella plicata. 
Labrum simplex, superné integrum, in collumellam desinens, posticé 
vel inferné subsinuatum.* 
Epidermis nulla. 
Animal littorale, amphibium, sed revera marinum, et branchiis spizans. 
The genus Melampus was formed by Denys de Montfort for the recep- 
tion of the Bulimus coniformis of Bruguiére. Lamarck had also once 
* This slight notch corresponds to the situation of the respiratory or anal 
orifice in the mantle, 
