142 GENERA AND SPECIES. 



556. hyalinus, ^ in. whorls 3 or 4, angulated on top, spire trun- 



cated, pillar straight above and curved 

 below, fold obscure, outer corner of mouth 

 angulated, outer lip bent at a third of its 

 length from the top. 



557- globosus, \ in. whorls 3, tumid; spire truncated. 



Trichotropis. (TRICHOTROPIDJE.) Plate xxiii. 



380. borealis, f in. shell turreted, whorls 7, convex and ribbed, 



basal groove angular. 



Triopa. (POLYCERID&.} Plate xxxiii. 

 606. claviger, f in. body white, gills white, tipped with yellow. 



Triton. (TRITONIDJE.) Plate xxv. 



459. nodiferus, 6 in. whorls 8 to 10, inside of outer lip with one 



row of ritiges. 



460. cutaceus, 2 in. whorls 5 or 6, body whorl with crested rib, 



inside of outer lip with 2 rows of ridges, 

 having excavations along the inner row. 



Tritonia. (TRITON 'IIDJE.) Plate xxxii. 

 602. hombergi, 5 in. head veil bilobed and fringed. 



alba, f in. head veil bilobed, with irregular points. 



plebeia, i in. head veil almost entire, with from 6 to 



8 points. 



lineata, f in. head veil entire, with 4 points. 



Trochus. (TROCHIDJE.) Plate xxii. 

 Without umbilicus 

 Over f in. 



352. granulatus, 1% in. shell dilated and rounded at the base. 



353. sizyphinus, i in. shell regularly pyramidal. 



Under f in. 

 351. millegranus, fin. marked with rows of granules. 



349. striatus, $ in. inside silvery, with rib near margin, suture 



indistinct. 



350. exasperatus, J in. inside silvery, with rib near margin, basal 



ridge encircling each whorl.suture indistinct. 



348. montacuti, $ in. inside silvery, without rib near margin, 



suture distinct. 



With umbilicus 



Under J in. 



340. glancus iV in - whorls 4. 



338. helicinus, J in. whorls 5, umbilicus narrow but deep. 



