ARISTZUS OCCIDENTALIS. 197 
tosus, really belong to Duvernoy’s genus Arisfeus. The branchial formula of 
Hemipeneus, as given on page 228 of the “Challenger” Report, is the same 
as in Aristeus Duvernoy, and the rostrum and general facies of these two 
species are like those of Aristeus rather than the typical species of Hemipeneus. 
Since the above was written, Wood-Mason’s paper on the Crustacea 
dredged off the coast of India by H. M. S. “Investigator” during 1890- 
91,* has come to hand. The author’s views concerning the affinities of the 
species just considered agree very closely with my own. A new generic 
name Aristopsis is given to the “ Aristeus” armatus group, for which Spence 
Bate had already furnished the provisional name Plesopeneus, and A. rostriden- 
tatus Bate is made the type of another genus, Aristwomorpha, on what scem to 
me too trivial characters, viz. the large number of rostral teeth, the presence 
of an hepatic spine, mucronate postero-lateral angles of abdominal somites, 
and the setaceous character of the dactyli of the last two pairs of thoracic 
appendages. If Aristwomorpha be recognized as a valid genus, it should 
probably include “ Avisteus?” foliaceus Smith, along with .A. rostridentatus. 
Two new species of Aristeus are described by Wood-Mason, one of which 
(Aristeeus coruscans) appears to be very closely allied to Avistwus occidentals. 
It differs from the latter, however, in having a shorter rostrum, and more 
strongly defined ridges and grooves on the sides of the carapace. Further- 
more, the three rostral spines are placed further forward in A. coruscans than 
in A, occidentalis, the posterior spine being directly over the posterior wall of 
the orbit in the former species, while in the latter this spine lies further back 
on the anterior gastric region. The dorsal carina which runs back from this 
spine along the median line of the carapace continues nearly to the posterior 
edge of the carapace in A. coruscans, while in A. occidentalis it does not ex- 
tend beyond the gastric region. 
The somewhat complicated synonymy of the genera Aristeus, Hemipeneus 
and Plesiopeneus appears to be as follows : — 
Aristzeus DuvERN. 
Aristeus Duvern., Ann. Sci. Nat., 2° Sér., XV. 104, 1841. Type, Peneus antennatus Risso. 
Aristeus Bate, Ann. Mag. Nat. Hist., 5th Ser., VIII. 187, 1881. (In part.) 
Hemipeneus Bate, Ann. Mag. Nat. Hist., 5th Ser., VIII. 186, 1881; Rep. Challenger 
Macrura, p. 299, 1888. (In part.) 
Aristeus Wood-Mason, Ann. Mag. Nat. Hist., 6th Ser., VIII. 278, 1891. 
Aristeus Fax., Bull. Mus. Comp. Zoél., XXIV. 215, 1893. 
* Ann. Mag. Nat. Hist., 6th Ser., VIII. 268 et seqq., 1891. 
