ARIST^US OCCIDENTALIS. 197 



tosiis, really belong to Duvernoy's genus Aristceus. The branchial formula of 

 Hemipeneus, as given on page 228 of the " Challenger " Eeport, is the same 

 as in Arista'iis Duvernoy, and the rostrum and general facies of these two 

 species are like those o^ Aristceus rather than the typical species of Ileiiiipcncus. 



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 afhnities of the 

 species just considered agree very closely with my own. A new generic 

 name Aristceopsis is given to the '' An'sketts " urnudus group, for which Spence 

 Bate had already furnished the provisional name Pksiojtencus, and A. rostriden- 

 tatiis Bate is made the type of another genus, AristceomorpJia, on what seem 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 Aristceomoipha be recognized as a valid genus, it should 

 probably include " Aristeus?" foliaceus Smith, along with A. rostridcnfaius. 

 Two new species of Aristivtis are described by Wood-Mason, one of which 

 {Aristceus coruscans) appears to be very closely allied to Aristcvus occideutalis . 

 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 furtlier 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 Aristceus, UemijHmeus 

 and Pksiopeneiis appears to be as follows : — 



Aristeeus Duvern. 



Aristeus Duvern., Ann. Sci. Nat., •2« Ser., XV. 104, 1841. Type, Penevs anteimains Risso. 



Aristeus Bate, Ann. Mag. Nai. Hist., 5th Ser., VIII. 187, 1881. (In part.) 



Hemipenmus Bate, Ann. Mag. Nat. Hist., 5tti Ser., VIII. 186, 1881; Eep. Challenger 



Macrura, p. 290, 1888. (In part.) 

 AristoBus Wood-Masou, Ann. Mag. Nat. Hist, 6th Ser., VIII. 278, 1891. 

 Aristceus Fax., Bull. Mus. Comp. Zool., XXIV. 21.5, 1893. 



* Ann. Mas. Nat. Hist., 6tU Ser., VIII. 268 ct scqq., 1S91. 



