THE HIPPOLYTIDZ 250 
other respects it agrees with Alpheus, and the motive of its 
name seems to be that as Beta stands close to Alpha in the 
Greek alphabet, Betceeus may be understood to stand close 
to Alpheus in generic character. Betceus malleodigitus, 
Spence Bate, from Fiji, has the finger of the first legs 
shaped like a mallet, in that respect resembling Alpheus 
malleator, Dana, and Alpheus obesimdnus, Dana. Betceus 
microstylus, Spence Bate, is distinguished with some doubt 
from Betwus cequimdnus, Dana. 
Family 3.—Hippolytide. 
The rostrum is of important size; the eyes are not 
covered oe the carapace; the mandibles may have a cutting 
edge and ‘palp, or be without one or both. ‘The first 
pair of trunk-legs have moderate-sized chele; the second 
pair are also chelate, with the wrist or fifth joint sometimes 
much and sometimes little subdivided. 
A dozen or more genera are included in this family. 
It is impossible here to do more than give an indication of 
the complexity to which Spence Bate has afforded a clue 
so far as his own views of the family are involved, but 
there is little agreement as yet as to the precise classifica- 
tion of some of the genera concerned. 
The Challenger collection gaye Spence Bate occasion 
to deal with nine genera, seven of which were named or 
established by himself. With these may be arranged 
Caridion, a name substituted by Goés in 1863 for the pre- 
occupied Doryphorus of Norman, and two genera that 
were instituted in 1869 by G. O. Sars, although in neither 
of them is the rostrum quite up to the importance de- 
manded by the character of the family. It must suffice 
here to refer only to the mandibles and the second pair of 
trunk-legs, using the word ‘wrist,’ for brevity’s sake, 
instead of saying in full the fifth joint of the second pair 
of trunk-legs. 
Platybéma, Spence Bate, 1888. Mandibles without 
cutting edge or ‘ palp.’ Wrist two-jointed. 
Caridion, Goés, 1863. Mandible with cutting edge 
and three-jointed ‘palp.’ Wrist two-jointed. 
