SUB-ORDER B 



It manifestly cannot be denied that Conularias and Hyolithes in particu! 



size, shell structure, and probably also conditions of existence, diH'i-n-d r<>n- 

 -idrrably from recent Pteropods. But in spite of the diH'rn-in-cs so strongly 

 emphasised by Pelseneer, the fact remains that of all shell-covered or^ani-m-, they 

 approach the Pteropods most nearly, and cannot with propriety be ivt.-rn-d to any 

 other group of the Mollusca. 



Family 1. Limacinidae. Cray. 



Shell thin, spiral, sinistral, with vitreous, paucispiral operculum. Tertiary and 

 Recent. 



The genus Limacina, Lam. (Spirialis, Eyd. and Soul. ; Embolux, Jeffreys), is of 

 sporadic occurrence in the Tertiary (Eocene and Pliocene). Valvatina, Watelet, 

 includes flat sinistral shells from the Calcaire Grossier of Paris, and Planorbella, Gabb, 

 contains similar forms from the Oligocene of San Domingo. 



Family 2. Cavoliniidae. Fischer. 



Shell symmetrical, thin, vitreous, ventricose, pyramidal, or conically tubiform, but not 

 spiral. Cretaceous to Recent. 



Cavolinia, Gioeni (Hyalaea, Lam. ; Gamopleura, Bellardi), (Fig. 1020). Shell 

 globose, laterally keeled and slit, acuminate pos- 

 teriorly ; composed of two unequally arched pieces, 

 one of which projects helmet-like above the other. 

 Recent, and fossil in the Italian Miocene and 

 Pliocene. 



Clio, Linn. (Cleodora, Peron and Lesueur ; 

 Balantium, Benson ; Flabellum, Poculina, Bellardi), 

 (Fig. 1021). Shell somewhat angular, compressed 

 dorso-ventrally, with lateral keels. A crest or rib 

 generally extends longitudinally along the back, and 

 usually projects. Upper Cretaceous to Recent. A 



common fossil in the Pliocene of Monte Mario, near Rome, and the vicinity of Messina 

 and Turin ; also in the Oligocene of the Mayence Basin, and in the English Crag. 



FIG. 1020. 



A, Cavolinia (Hyalaea) trident" f", Korsk. 

 "5, (7, C. (Guinoplcurd*) tit": 



FIG. 1021. 



A, Cleodora pyramidata, Linn. Pliocene; Monte 

 Mario, near Rome. B, JMantium recurcu;-. \. 

 Adams. Recent. Animal with shell (after Adams). 

 C, Vaginella depressa, Daudin (Clewlora strait* 

 Desh.). Miocene ; Dax, near Bordeaux. 



A, Styliola recta, Lesueur. Recent (after 

 Adams). B, Stuliola striatnl<>, Novak. !>'- 

 vonian (Etage H); Hlubocep, Bohemia. 3 /i- 

 C. Styliolfl davuku, Barr. Devonian (Kta-r H): 

 Hostin, near Prague, Bohemia. Several in- 

 dividuals on slate-fragment. Vi- 



Sub-genus : Styliola, Lesueur (Creseis, Rang ; Crisia, Menke), (Fig. 1022). Shell conical, 



