550 Mr. L. A. Borradaile on the 
Key to the Subgenera of Axius. 
I. Eyes pigmented. Flat area of back and cervical 
groove well marked. [Antennal thorns large. | 
1. Pleurobranchs on legs 2-4 ........055..2000% Axius. 
2.QNo pleurobranchssmey. mbt. obese aa eran Neavius. 
II. Eyes pale. Flat area of back and cervical groove 
more or Jess indistinct. 
1, Pleurobranchs on legs 2-4. Antennal thorns 
large. 
a. Gills on second maxilliped ..........+.+05- Iconaxiopsis. 
b. No gills on second maxilliped..........+... Ficonarius. 
2. No pleurobranchs. Antennal thorns small.... Paraxws. 
Key to the Subgenera of Calocaris. 
i Antennal thorns larve's aioe. fhe e.2 ee eee Calastacus. 
II. Antennal thorns small: ...... yareie tant hese ge te ererabeys Calocaris. 
Key to the Genera of the Laomedide. 
I. No lash to exopodite of first maxilliped. First leg 
with stout chela. Second leg simple ........ Laomedia. 
II. A lash to exopodite of first maxilliped. First leg 
with slender chela. Second leg subchelate .... Jaxea. 
Key to the Subfamilies of the Callianassidze. 
I. Rostrum large. Legs of first pair equal. No ap- 
pendix interna on abdominal limbs 3-5........ UpoGEBIIN. 
II. Rostrum small. Legs of first pair unequal. An 
appendix interna on abdominal limbs 3-5 ...... CALLIANASSINE, 
Key to the Genera of the Upogebiine. 
I. Legs of second pair simple. 
1. Legs of first pair chelate or subchelate. Last 
limb not longer than telson ................ Upogebia. 
2. Legs of first pair simple. Last limb longer than 
LELSON Foie --delelatee et iote they eto ets eee ees Gebicula. 
II. Legs of second pair chelate ........ ah a DAs Bigea. 
Key to the Subgenera of Upogebia. 
I. Legs of first pair chelate. No tooth on the fore 
edge of the carapace over the antenna ........ Gebiopsis. 
Il, Legs of first pair with “ thumb ” distinctly shorter 
than movable finger. A tooth on the fore edge 
of the carapace over the antenna ............ Upogebia. 
Key to the Genera of the Callianassine. 
I. No gill-like filaments on abdominal limbs. Second 
abdominal limb unlike third to fifth. No masti- 
gobranchs on legs. 
a. Plates of tail-fin not deeply sculptured. Ischio- 
podite and meropodite of third maxilliped 
broader than carpopodite and propodite...... Callianassa. 
b. Plates of tail-fin deeply sculptured. Ischiopodite 
and meropodite of third maxilliped not broader 
than carpopodite and propodite ............ Glypturus. 
II, Gill-like filaments on abdominal limbs 2-5, which 
are all alike, Mastigobranchs on legs 1-4 ,,,., Callianidea. 
