No. 394.] MWORTH-AMERICAN INVERTEBRATES. 823 
Genus Palinurus (F P An 
. P. longimanus Milne-Edwards S (?) 
Family EEA A 
Genus Scyllarus Fabr. Branchiæ 21. 
27. Gastric region without spines; posterior border of third abdominal 
segment regularly arcuate S. eguinoxialis Fabr. S 
27. Gastric region with bidentate projec third abdominal segment 
with a strong knob S. nodifer Stimpson S 
Genus Avctus Dana. Branchiæ 19. 
28. Antepenult segment of antenna with two teeth on external margin; 
sternal segments without conspicuous spines 
A. americanus Smith S 
28. Antepenult segment of antenna with three teeth, sternal segments with 
conspicuous spines A. depressus Smith M 
5 oo: i 8 
Naushonia crangonoides; (2) Callianassa longimana; 
Callianassa stim 
Chelæ of Thalassinoid Crustacea. — (1) 
ia pugettensis; (6) stimpsoni; 
(3) Callianassa gigas; (4) Gebia affinis; (5) e 
(7) Axius serratus; (8) Callianassa californie 
Group THALASSINOIDEA. 
Family CALLIANASSIDÆ. 
Genus Callianassa Leach. Chelipeds unequal in size, carapace smooth 
and glossy. 
. Meros of larger cheliped serrate below, palm nearly twice length of 
29 
carpus C. grandimana Gibbes S 
29. Meros of oie eclek with a ico GT spine below . 30 
: : ee 
30. Carpus and palm sub-equal . 
30. Carpus about twice the length of ie palm 32 
31. Meros short, tapering towards distal catresaity ¢ i OER without distal 
spines : i : . C. longimana Stimpson P 
