MOLLUSC A— GASTROPODA. 599 



weak ; no umbilicus or lirse. 

 CLXVII. Pseudolathyrus. 

 2' '. Plications in form of slender lines or 

 ridges. 



CLXIIIA. Barbarofusus. 

 b. Sutures not so deeply impressed ; aper- 

 ture less rapidly contracting, ribs and 

 spirals fainter ; typically a strong, ob- 

 lique, anterior columellar fold. 



C L I X . Fasciola ria . 



i8f. Shell strongly spinose CLXXV. Vasum. 



b/. Spire short and thick, less than apertural length 57. 



57. Whorls moderately embracing jj / . 



JJ'. Aperture abruptly contracted to anterior canal, ribbed 



and spiralled : I9f. 



19-f-. Columellar and outer lip lirate. 



CLXIII. Heilprinia. 

 I9f. Columella with single tooth. 



CLXXI. Odontofusus. 



19-f. Columella smooth, canal short, slightly curved. 



CLXXVIII. Urosalpinx. 



'. Aperture not abruptly contracted 20f. 



20f. Columella with strong plications XXX' 



XXX- Whorls round or moderately angulated with 

 continuous ribs, spinose or tuberculated 



on the angle CLXXXV. Volutilithes. 



XXX- Whorls angulated and generally spinose ; 

 aperture broad in front, canaliculated pos- 

 teriorly ; plaits numerous. 



CLXXXVI. Voluta. 

 XXX- Whorls rounded in adult only, and without 



ribs or spirals CLXXXVII. Aurinia. 



XXX- Whorls round, smooth throughout c. 



c. Aperture sharp behind, widening forward, 



oblique grooves on columella... j'. 

 j / . Surface smooth. 



CLXXXVIII. Oliva. 

 3' . Surface with vertical striations. 



CLXXXIX. Olivula. 

 e. Aperture more or less patulous, strong pli- 

 cations on columella. 



CLXXVI. Caricella. 



57. Whorls strongly embracing, rounded kk'. 



kk'. Aperture abruptly contracted to long canal. 



CLIII. Pyropsis. 



kk'. Aperture not contracted 2if. 



2if. Aperture wide and patulous CXLV. Pyrula. 



2 If. Aperture narrow... XXXX- 



XXXX' Inner lip not expanded d. 



d. Aperture sharp behind, widening forward. 



S'- 



