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ARIST^.US OCCIDENTALIS. 



197 



tosusy really belong to Duvernoy's genus Arisimus, The branchial formula of 

 Ilemhpeneus^ as given on page 228 of the ^'Challenger" Report^ is the same 

 as in Aristwiis Duvernoy, and the rostrum and general facies of these two 

 species are like those of Arislwtis rather than the typical species of Ilcmipcneiis . 



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 Aristwopsis is given to the ^' Aristceiis " armahis group, for which Spence 



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Bate had already furnished the provisional name Pksiopeneiis, and A. rostridcn- 

 talus Bate is made the type of another genus^ Aristoioniorpha, on what seem to 

 me too trivial characters, viz. tlie large number of rostral teeth^ the presence 

 of an hepatic spine, mucronate postero-latcral angles of abdominal somites, 

 and the setaceous character of the dactyli of the last two pairs of thoracic 

 appendages. If Aristwomorpka be recognized as a valid genus, it should 

 probably include '^ Aristcus ? '' foliacms Smith, along with A\ rostridcnfaius. 

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

 {Arislccus coriiscans) appears to be very closely allied to Aristmis occidenlalis. 

 It differs from the latter, however, in having a shorter rostrum, and more 

 strongly defined ridges and grooves on the sides of the carapace. Furtlier- 

 more, the three rostral spines are placed furtlier forw\ard in A. coriiscans than 

 in A, occidentalism the posterior spine being directly over the posterior w\all 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, occidcniaUs it docs not ex- 

 tend beyond the gastric region. 



The somewhat complicated synonymy of the genera Aristwus^ Hemipencus 

 and Pksiopcncus appears to be as follows : 



Aristaeus Duvern. 



Aristeus Diivern., Ann. Sci. Nat., 2^ Ser., XV. 104, 1841. Tj^pc, Feneus antennatiis Eisso. 



Aruteus Bate, Aon. Mag. Nat. Hist., 5t]i Ser., VIII. 187, 1881. (In part.) 



Ilcmipenmis Bate, Ann. Mag. Nat. Hist., 5tli Ser., VIII. 186, 1881; Eep. Challenger 



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

 Aristmus Wood-Mason, Ann. Mag. Nat. Hist., 6th Ser., VIII. 278, 1801. 

 Aristoius Fax., Bull. Mus. Coinp. ZooL, XXIV. 215, 1803. 



* Aim. Mag. Nat. Hist., 6ih Ser., YIIL 3G8 et scqq., 1891. 





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