1080 General Notes. (October, 
undatum. The facts observed were, that every change in the 
constitution of sea water is, in the long run, fatal, but that there 
is great difference in the rate of the toxic action of any one solu- 
tion upon the same animal, and great range in the resistance of 
different mollusks to the same solution. The gasteropods suc- 
cumbed before the bivalves, yet Littorina, defended by its opercu- 
lum, resisted longer than the non-operculate and canaliculated 
` Tritonium. The mussel died before either of the Venerida, and 
V. decussata showed a vitality far surpassing any of the others. 
The salts of soda and magnesia were far less fatal than those of 
potash, and also sustained life longer than chloride of sodium 
alone, but in the latter they extended their siphons a much larger 
portion of the time than in sulphate of magnesia or sulphate of 
soda. Death in the case of the bivalves arrived from muscular 
enfeeblement, at last resulting in inability to close the valves. 
Crustaceans.—In the Transactions of the New Zealand Insti- 
tute, C. Chilton describes upwards of twenty new species 
Crustacea, principally belonging to the Tetradecapoda, but in- 
cluding two Brachyures, Hymenicus marmoratus and Hymenosoma 
lacustris. Among the species are several obtained from a well 
sixteen feet deep, one of which, the isopods Crumegius fo 
and Phreatoicus typicus, are without eyes. This 
a Macrural. 
English crayfish and Paranephrops setosus. 
Arachnids.—Mr. C. Chilton, in the Transactions 
Zealand Institute, describes a sea-mite which he p 
genus Halacarus Gosse, two species of which have 
viously described from England. 
of the New 
laces in the 
* j K . ; us 
eneidids (Proc. U. S. Nat. Mus., 1883) gives the views of eet 
naturalists on their affinities, but states as the result yee thus 
examination, that (1) the ventrals have true spines, | crani” 
would be Acanthopterygians of Cuvier; (2) the 
is simple, and there is no “tube.” Thus these fi 
’s sub-or™. 
rder Disc™ 
A 
hich they have 
nianus 
between the 
been pre 
