ASTACUS FOUND IN UPPER CANADA. 217 
shall merely copy the description given in that book, as it is too well 
known to require further notice. 
Astacus Bartonii, body with scattered punctures, rostrum mucronate 
concave elongated, suddenly attenuated, but with lateral angles rather 
than spines at the point of attenuation, no spines on the thorax; an 
acute triangular spine rather exceeding the rostrum in length articu- 
lated to the outer side of the base of the external antennze, below the 
base of the spine on each side an oculiform tubercle, movable finger 
slightly shorter than its opposite, and a number of faveole or pits in 
such a regular series on both, as to produce the appearance of one or 
more elevated lines, Carpus with a deep furrow on its upper surface 
and one or more spines on its inner angle; shield with a transverse 
lunate furrow. The first segment of the middle caudal lamella, with 
one or two short spines on each side. Colour of the body and claws, 
greenish brown, tips of the rostrum of the hands and feet (and sexual 
appendices of the male) reddish; lighter beneath. 
The other Canadian species, supposed to be undescribed may be 
thus characterised :— 
Astacus fodiens (mihi) rostrum broad, short, triangular, acute, 
margined, concave throughout its length, edges smooth without spines. 
Carapace robust, rounded, much deeper than in Astacus Bartonii, 
plentifully marked with minute pits, granulated towards the stomachie 
region, not spinous. Claw stronger than in the preceding species, the 
movable finger with a strong tooth on the internal margin, external 
margin deeply denticulated, a well defined ridge along the whole 
length. Thumb with the internal margin less strongly toothed, smooth 
externally. Carpus with a strong spine on its inner margin and a deep 
furrow on its upper side, length 3 to 4 inches. Swamps and wet 
places common. 
The author of the Natural History of the State of New York, and 
M. Edwards, both described an Astacus under the name of affinis, 
the former giving the habitat as the River Delaware, the latter as the 
rivulets of North America. Their two descriptions do not agree. In 
the first I see no resemblance to my Astacus, in the second ‘a great 
deal : so much so, that I think we may, perhaps, both mean the same 
animal. M. Edwards gives, as his authority, Say’s Crustacea of the 
United States, a work I have not been able to consult, but with which 
I should imagine the American author must be familiar, I shall 
quote both these descriptions that the members may compare them, 
Vou. VIII. R 
