RISSOA. 23 



brides ; and Mr. Barlee sent me specimens from Shet- 

 land. It is rather common in the Channel Isles^ and 

 occurs there at the base of seaweeds on the recess of 

 high springtides. Fossil in Sussex (Godwin- Austen) ^ 

 Largs in Ayrshire (Landsborough) ^ Palermo and Ta- 

 rento (Philippi) . Its northern limits comprise Norway, 

 Sweden_, and Holland; and southwards it ranges along 

 the shores of the North Atlantic as far as the Canaries 

 (M'Andrew), and of the Mediterranean on both sides : 

 the depths given by different obserA ers vary from 4-70 f. 



Mr. Clark remarked the rapidity and freedom of its 

 movements. In showing that it is a true Rissoa, he 

 said '^ it is a very simple creatui'e.^^ This, of coui'se_, he 

 meant in a zoological and not psychological sense. Spe- 

 cimens from Teneriffe and Spezzia are uncommonly 

 small. 



It is the Turbo lacteus of Donovan — ^in index, '^ Turbo 

 parvus [lacteus),'' — T. crassus of Adamses work on the 

 Microscope, T. plicatus of ]\IUhlfeld, R. exigua of 

 Michaiid, and R. carinata of Philippi. R. costata of 

 Desmarets is the R. variabilis of Miihlfeld, and very 

 different from the present species. 



C. Mostly ribbed lengthwise and spirally striated ; outer lip 

 usually strengthened by a rib. 



12. R. PARVA"^, Da Costa. 



Turbo parvus, Da Costa, Br. Conch, p. 104. E.parva, F. &H. iii. p. 98, 

 pi. Ixxvi. f. 2, 6, Ixxvii. f. 6, 7, and Ixxxii. f. 1-4. 



Body pale -yellowish- white, with a purplish blotch in the 

 middle, and sometimes more or less tinged in other parts with 

 the latter colour : palUal filament occasionally protrnded : snout 

 narrow and deeply cloven : tentacles whitish, extensile, some- 

 what flattened, finely scalloped at the edges, and covered with 

 minute ciha, which are not easily perceptible unless by using 



* Little. 



