422 



MONOTOCARDIA— GYMNOGLOSSA — RACHIGLOSSA 



CHAP. 



Fig. 279. — Carinaria mediterranea Lam. 

 Naples : a, anus ; 6r, branchiae ; /, foot ; i 

 intestine; m, mouth; p, penis; s, sucker 

 sh, shell ; t, tentacles, x k- 



a very small spiral shell. Carinaria (Fig. 279) has a rugose 

 translucent skin, visceral sac sub-median, apparently peduncu- 

 lated, covered by a capuliform shell. The larval shell, which 

 persists in the adult, is helicoid. 



Fam. 2. Atlantidae. — Shell spiral, operculate, covering the 



animal. Branchiae in a 

 dorsal cavity of the man- 

 tle ; foot trilobed, with a 

 small sucker on the meso- 

 podium. 



The shell of Atlanta 

 is discoidal and sharply 

 keeled, while that of Oxy- 

 gyrus is nautiloid, with the 

 spire concealed, no keel, 

 aperture dilated. 



(c) Gymnoglossa. — 

 Radula and jaws absent; 

 proboscis prominent, sexes probably separate, penis present, i 

 The section is probably artificial and unnecessary, the families 

 composing it being, in all probability, Taenioglossa which have 

 lost their radula in consequence of changed conditions of life 

 (pp. 79, 225). 



Fam. 1. Eulimida.e. — Proboscis very long, retractile, mantle 

 forming a siphonal fold; shell small, long, subulate, polished ;| 

 suture shallow, aperture continuous, operculum present or absent. I 

 Animal often parasitic, sucking the juices of its host by its long I 



proboscis. Trias . Genera : Uidima (subg., Suhularia Ar- 



cuella, Apicalia^ Mucronalia^ Stiliferina^ and others), Stilifer^ 

 Scalenostoma^ Niso^ and Hoplopteron. 



Fam. 2. Pyramiidellidae. — Tentacles auriform, proboscis as in 

 Eulimidae, a prominent mentum or flap under the buccal orifice ; 

 shell usually small, conical ; suture shallow, apical whorls (the 

 embryonic shell) sinistral (p. 250), operculum corneous, pauci- 



spiral; nucleus excentrical. Trias . Geneva: Pyramidella 



(subg., Syrnola^ Otopleura^ Chrysallida^ Mumiola)^ Odostomia, 

 Eulimella^ Murchisoniella^ Turhonilla (subg., Dunkeria and 

 Cingulina. 



(c?) RACHIGLOSSA (p. 220). — Proboscis long, retractile; 

 siphon distinct, radula without uncini, sometimes without 

 laterals ; teeth strongly cusped ; shell generally wholly external. 



