Quarterly Journal of Conchology. 83 



IX. The Arctic type, comprising few of the most northern 

 shells, of which none are found on the coasts. 



Of the Land and Fresh-water shells, the author enumerates 

 71 species, 40 land and 31 fresh-water, but the occurrence of 

 some of these he has not been able personally to verify. 



There is an absence of some species which we should have 

 expected to occur, but doubtless a more extended and closer 

 search will reveal others, especially amongst the more minute 

 species. We however hail it as a solid contribution to our 

 better knowledge of the fauna of Dorset. 



The following articles appear in the April number of the 

 Journal de Conchyliologie 1875. 



Crosse, H. — Note sur le Phyllaplysia Lafonti, Fischer 

 (Note on P. Lafonti, F. ), pp. 1 01— 104. 



This very rare naked mollusk was observed by M. Crosse 

 in the basin of Arcachon. It never swims, but crawls in a 

 very similar way to a slug, progressing however very quickly. 

 It adheres so firmly to any smooth surface that it is very 

 difficult to detach it. 



Fischer, P. — Remarques sur la coloration ge'nerale des 

 coquilles de la cote occidentale d'Amerique (Remarks on the 

 general system of colouring of the shells of the West Coast 

 of America), pp. 105 — 112. 



As a general rule, whilst the shells of the Arctic seas 

 are obscurely coloured, and those of temperate seas not .very 

 brilliant, the shells of the tropics are handsomely colored and 

 ornamented with variegated spots, lines and bands. The West 

 Coast of America forms however a striking exception from 

 the number of shells of a black or very dark color, many befering 

 such appropriate names as "ater" "maestus" "funebrali.s" "tristis" 

 &c. Dr. Fischer gives a list of the most striking examples 

 of this (from which however Miirex radix is somewhat un- 

 accountably omitted) and then proceeds to consider the causes 

 which may have produced this funereal fauna. He mentions five 

 — the narrow extent of the torrid region, the cold currents both 

 North and South, the absence of coral reefs, the uniformly North 

 and South direction of the coast, and the poverty of the terrestrial 

 fauna ; but he at the same time acknowledges that these circum- 

 stances are insufficient to account for the fact, and that a complete 

 explanation has not yet been found. 



