338 Agassiz’s Contributions to the 
some relations to the Squilloids—the aberrant Order among the 
capods.* 
ay, as a whole, the cephalothorax and abdomen. : 
h mi range, a d on grades of — 
concentration, but affecting the cephalothorax mainly, and leat: 
ing to the highest degree of cephalization. 
* The subdivisions of Crustacea which have been mentioned, are the following : 
The grouping differs somewhat from that given in the writer's Report on 
CRUSTACEA. 
Order I. DECAPODS, 
ORDERS OF 2D GRADE, 
I. BRACHYURANS. 
Orders of 3d grade, 
1, Maioids. 
2. Cancroids and Grapsoids. 
8. Corystoids, 
4. Leucosoids. Aberrant. ves 
Appendix. Anomoura—Hmbryonic in typ? 
Il. MACROURANS. 
1. Astacoids, 
2. Caridoi 
8. Penwoids, ais 
i i i t, ; 
4. nana saree se in types 
II. GASTROURANS or SQUILLOIDS. 
IL TETRADECAPODS. 
If. ENTOMOSTRACANS, 
