552 Characteristics of the Genus Dieneeia West wood. 



Next, I do not admit, so far as principle is concerned (although 

 Mr. Hailstone is perfectly welcome to the imposition of the 

 names of the animals in question), that he is at liberty to 

 claim the insertion of fresh trivial names which may appear 

 more adapted to them ; because^ although he caught and de- 

 scribed the animals, yet the trouble of ascertaining whether 

 they had been previously described by crustaceologists or not 

 was mine : and every naturalist is aware that this a greater 

 task than the mere describing of an animal. Unquestionably, 

 therefore, as the manuscripts were placed in my hands in an 

 imperfect state [so far as the absence of identification and 

 denomination, which are the points in question], without the 

 slightest intimation that Mr. Hailstone wished the subject to 

 be again laid before him in case the species were undescribed, 

 I had the right, in order to render the paper complete, to 

 apply a specific name ; which must stand, because, having been 

 once published, " nomina trivialia nunquam absque sum ma 

 necessitate mutanda sunt." — Fabr, 



I gave [p. 274, 275.] my reasons for suggesting the name 

 of rubra to the Cryptopthalmus ?, which I need not repeat. 

 Mr. Hailstone has given (p. 395.) it as Hippolyt^ macrocheles, 

 without any doubt as to its genus. But, taking into con- 

 sideration Mr. Hailstone's several observations thereupon 

 [272, 273. 394], and my own [274-.], I do not now hesitate 

 to raise it to the rank of a distinct genus, under the name of 



Dieneeia (Dienekes, continuous ; the abdomen not gibbose 

 in the middle). Antenna? superiores bisetosae. Abdomen supra, 

 in medio, haud gibboso-elevatum. Rostrum perbreve, haud 

 serratum. Cephalothorax oculos obtegens. Pedes antici 

 maximi, chelis maximis. Pedes secundi anticis vix longiores, 

 graciles, carpo articulato, apice chelis minutis armati. Typus 

 Hippolyte ? rubra, Mag. Nat Hist., vol. viii. p. 272. fig. 31. 



If Mr. Hailstone be correct in giving [p. 395.] his Porcel- 

 lana [p. 265. 268 — 270.] as identical with Leach's L'mnedna 

 in the British Museum, although Mr. Hailstone's specimens, 

 which I had before me at the time I wrote my remarks, neither 

 agreed with Desmarest's nor Gray's descriptions of that species 

 (as, in fact, I noticed [p. 267.]), this latter name, as well as 

 that of Leach// of Gray, must also be expunged, and that of 

 hexapus, given to it by Linnaeus and Latreille, applied in its 

 stead. Observe, moreover, that the hexapus of Linnaeus 

 formed the type of Leach's genus Pisidia; a genus founded 

 upon characters notably less strong than those of Dieneeia 

 proposed above. — J. O. PVestwood. The Grove, Hammersmith, 

 August, 1835. 



I A Correction (p. 394. 552.) of the Error in the Engraving 



