86 NATURAL SCIENCE [August 
Astacula by having the flagellum of the second antennae more than 
four-jointed. Nature lures us on by showing species after species in 
which the joints are more than four, and, when we are purely 
satisfied with our generic character, brings to view Arcturus 
multispinis, in which the flagellum in question is single-jointed. 
When Astacilla has established a character for preferring shallow 
water, Mr Jules Bonnier describes the remarkable Astacilla giardi 
from a depth of more than 500 fathoms, and now from 1825 fathoms 
comes Mr Benedict's A. caeca, Mr Beddard has pointed out 
that the genera Arcturus and Astacilla “form almost the only 
exception to the general statement that the deep sea Isopoda are 
blind,’ and now Mr Benedict’s last-mentioned species comes as an 
exception to this exception, being a blind Isopod from the deep 
sea. 
In a second paper, simultaneously published in the same 
Proceedings (vol. xi., pp. 53-55), Mr Benedict describes two new 
Californian species, both of which he assigns to the genus Jdotea, 
relying for the limits of that genus on the monograph of the 
Idoteidae by E. J. Miers, published in 1883, It is rather surprising 
that he takes no notice of the far more recent discussion of this 
family by Mr Adrien Dollfus in the Fewille des Jeunes Natur- 
alistes, November 1894, and February 1895. Few students who 
have read the papers by Mr Dollfus will be ready to retain Mr 
Benedict's two new species in one and the same genus. 
Miss Harriet Richardson, also in the same publication (xi1., 
pp. 39-40) describes and figures a new species of ga, closely 
related to Aga tridens, Leach. The discriminating characters do 
not seem to be all of them quite convincing. One of these 
depends on the number of joints in the flagella of the antennae, 
the new Aga ecarimata having on the second pair ten joints, 
while Leach’s species has nineteen. It is true that the number 
nineteen is assigned to it by Schiddte and Meinert, but Bate and 
Westwood say that the number is about twelve, and it may be taken 
for granted that there is no fixity in this respect to depend on 
among specimens of different ages and different sizes. The relative 
length and breadth of the body is likely to prove an equally unstable 
character. The new species is said to be more than thrice as long 
as broad, and the figure given agrees with this measurement, but so 
does the figure of 4ya tridens given by Schiodte and Meinert, 
though that drawn by Bate and Westwood is of a more portly 
habit. 
Under present conditions of human existence the scattering of 
scientific information remains unavoidable, so that one can merely 
note, without astonishment or disapproval, that one new species of 
ga obtained by the U.S. Fish Commission steamer ‘ Albatross’ 
