370 LITTORINID AL. 
more circular than in the last species, but, though paucispiral, 
the turns are less distinct, the oblique striz of imcerement 
coarser, and the colour imstead of bemg clear white is a dull 
yellow. All this is different in the ‘proxima,’ 
The examples now described are the only two that have 
occurred of this rare animal; it and the ‘proxima’ were 
placed in the same glass, and, being lively, I had good oppor- 
tunities for comparison ; the animals are organically different, 
but I think the ‘proxima’ is a greater departure from the 
Rissoidean type than the ‘vitrea’; still it will probably re- 
main with the Rissoe, though some of the specialties are on 
the verge of generic deviation. 
In the remarks on these species I fear that conciseness 1s 
neglected, but the confusion in which they have long been 
enveloped must be the apology, as, without the present close 
examination, the doubts of their identity or distinctness 
would still have remamed, and the slight, though constant, 
difference of contour in the two would by many be considered 
accidental. 
It may be useful to the shell collector, to the younger 
student, and as a memorandum of the remaining desiderata 
of this genus, to offer a few short remarks on all the British 
Rissoe not enumerated above. 
The animal of the elaborately sculptured R. striatula, the 
most elegant of the Rissoe, if it be one, still escapes observa- 
tion. I have taken some delicate specimens in the coralline 
district, and yet hope to see the mhabitant. 
The R. lactea of Michaud I do not know, but from the 
figure in ‘ Brit. Moll.’ I should have judged it a variety of the. 
R. reticulata, one of the large, short, tumid shells, and would 
have said the same of the R. abyssicola, if it had. not been 
considered distinct by Professor Forbes. The R. crenulata is 
the well-known Turbo cimex, as the R. calathus is the old 
‘calathiscus’ of authors: neither of the animals are recorded. 
The R. Zetlandica is a well-established northern species, but 
the inhabitant is unknown. 
