SDB-CLA I! 



PLATYPOI )A K I T 1 1 Y N KM 1 A 



4*3 



Borsonia, Bellardi (Fig. 1000). Outer margin with a shallow n<it<-h ; canal long 

 and straight; columella with one or two folds; operculum unknown. Eocene to 

 Recent. 



Mangilia, Risso (Figs. 1001, 1002). Small, fusiform, imperforatc, ami typically 

 with longitudinal costae or >w-]Iings. Aperture commonly narrow, with a short, 



IMC:. 1000. 



Borsonia Deluci, 

 Nvst. Lower Oligo- 

 cene; Lattdorf, near 



FIG. 1001. 



Mangilia angusta, 

 Jan. Pliocene ; 

 Occiano, near Pisa. 



FIG. 1002. 



A, Mangilia (Clathur- 

 ella) stroinbilltis, Duj. 

 Miocene ; Kienberg, 

 near Vienna. /-', M. 

 (Homotoma) retinilntu, 

 Brocchi. Pliocene; 

 Sassnola, near Modena. 



Fi.;. 1003. 



/mini) r a I jn i- a 1 a , 



Brocchi. Pliocene; 

 Siissnola, near 

 Modena. 



truncated canal ; inner margin varicose ; sinus near the suture. Outer margin usually 

 somewhat thickened, posteriorly with shallow notch. Tertiary and Recent, 



Allied genera are the following : Clathurella, Carp. (Fig. 1002, .4) ; Homotoma 

 (Fig. 1002, B) ; Atoma, Bellardi ; Daphnella, 

 Hinds, with sub-genus Raphitoma, Bellardi (Fig. 

 1003); Eucythara, Fischer, etc. 



Family 4. Oonidae. Adams. 



Shell convolute, turbinate, or sub - cylindrical, 

 generally smooth. Spire short, conical or flattened. 

 Aperture long, narrow, anteriorly notched. Outer 

 lip sliarp, sometimes with an anal sinus below the 

 suture. Columella smooth. Operculum horny. 

 Cretaceous to Recent. 



This family is now enjoying its acme of 

 development, having entered upon its ascendency 

 during the Tertiary. The typical genus Conus, 

 Linn. (Fig. 1004), is divided by malacologists 

 into numerous sub -genera, connected with one 

 another by intermediate forms, 

 the Cretaceous. 



Conorbis, Swains. Characterised by a high 

 spire, and a curved, outer lip, which is deeply notched posteriorly. Eocene and 

 Oligocene. 



FIG. 1004. 



A, Conus jwndtrostis, Brocchi. Miocene ; 

 It is initiated in Lapugy, Transylvania. Ji, r. petH 



Desh. Calcaire Grossier ; Griguon, near 

 Paris. 



Sub-Class 2. EUTHYNEURA. Spengel. 



Gastropods in which the visceral nerve commissures are not crossed, but form a 

 loop ; the sexes are united (hermaphrodite) ; and the heart is often in front of the gill. 

 Shell spiral or saucer -shaped, frequently vestigeal or absent ; operculum generally wanting. 

 Radula generally multiserial. 



