1908] - Decapod Orustaceans. 15 
figs. I & and 22) that this oral appendage in UC. crassipes bears a 
far closer resemblancee to the corresponding limb in Paraxius altus 
Sp. B. than to that of FE. acutifrons SP. B. 
 2nd Maxilliped. In the Morphological Chapter of the Chall. 
Ex. Vol. XXIV page XXXVIII, Spence Batz in his remarks 
about the 2nd Maxilliped (i. e. 1st Gnathopod) states: The coxa 
almost universally has åa mastigobranchial plate attached, which is 
generally of small size and varies in form, and has very con- 
stantly å branchial plume attached to it!) and occasionally 
a second or arthrobranchial plume attached to the membranous 
artieulation.” The species under discussion therefore coineides exactly 
with Spence BaTtrk's morphological description. On the other hand 
this is not the case with Spence BarkE's own species Kiconaæius 
aecutifrons, of which he says (page 43 of the same work): *A prodo- 
branehial plume in å rudimentary condition is attached 
to the base of all) the mastigobranchiae, except that of the first 
gnathopoda*) and the penultimate pereiopoda.” Ås far as the 
mastigobranchiae of the same species are concerned, it is shown imme- 
diately before the above quotation that they are found, attached to the 
coxa of every appendage from the posterior pair of siagnopoda 
s.+ (i e. 1st Maxilliped) . . . . to the fourth pair of pereiopoda 
”. We gather then from this statement that the 1st maxilliped 
of E. acutifrons is furnished with a podobranchia, but not the suc- 
ceeding 1st gnathopod (or 2nd Maxilla): the third and following 
limbs on the other hand as far as and ineluding the 4th pereiopods 
are supplied with podobranchiae. The absence of podobranehiae on 
the first pair of gnathopods is at any rate clearly enough maintained 
in the case of E. acutifrons, whereas U. crassipes differs in that it 
is in possession of them. Similarly in OC. erassipes, the arthro- 
branehiae begin with these gnathopods, whereas according to SPENCE 
Bartz's table (page 43) they are first found in the ease of E. acuti- 
froms on the I1st pereiopods. It may be mentioned moreover, as 
showing a difference between UC. crassipes and E. acutifrons, so far 
as this gnathopod is concerned, that while the ecphysis of the latter 
species "terminates in å sharp point only, instead of å multartieulated 
lash” —a fact utilised by Srencz Bars to distinguish it from Paraxius, 
—the ecphysis of U. erassipes is like that of Parazxius in possession 
1) The interspaced letters are mine. 
