TRIFORIS. 187 



T. TRisTOMA, Blainv. PI. 39, fig. 42. 



Whorls 15, triseriately tuberculated, the upper row strongest, 

 suture whitish, channeled, with a minute row of granules ; yellow- 

 ish-chestnut, with a row of darker spots between the granules of 

 the lower series. Length, 12 mill. 



Aush'alia. 



The species was based upon its " three-mouths," and can no longer 

 be identified with certainty. 



T. EXiLis, Dunker. PI. 39, fig. 45. 



Whorls 10-11, triseriately granose, suture narrow, not deep^ 

 brownish, with a lighter line. Length, 5 mill. 



Japan. 



T. PERVERSUs, Linn. PI. 39, figs. 44, 51. 



Whorls about 16-18, flat, clathrate, with three series of rovolving 

 and numerous longitudinal riblets, the intersections nodulose, body 

 whorl with four spiral series, below which are two spiral ribs ; yel- 

 loAvish brown, or chestnut color. Length, 15-30 mill. 



Europe, Canary Is. 



The synonyms are T. Maroccanus, Brug., T. radula, Olivi, T. 

 reticulatus, Donov., T. granulosus, Scacchi, T. tubercularis, Blainv., 

 T. seriatus, Muhlf , T. inversus, Costa, T. Savignyanus, Chiaje, to 

 which European authors often add Cerithmm pusillum, Pfr. 



Var. Benoitianum, Arada^. 



Established on a single individual 34*5 mill, long, with four series 

 of granules on the spire and five on the body Avhorl, lip mjich 

 dilated. 



Ognina. 



Var, ADVERSA, Montg. Fig. 51. 



Shell smaller, 15 mill. long. This :^ var. minor, Monts., and T. 

 Belli. Wood. It is found also on the California coast — at least no 

 diflferences have been detected between these and European 

 examples. 



Thei'e are also vars. cylindrata, obesula and attenuata, Monts., 

 founded upon the form of the shell, and the following color-varieties. 



Var. BICOLOR, Mts. Brown, with white tubercles. 

 Var. cixcTA, Mts. Brown, with a white median zone. 

 Var. PALLESCExs, Jeffreys. Light fawn color. 

 Var. LACTEA, Mts. AVhite. 



