498 MR. C. SPENCE BATE [NoV. 24, 



4. On SOME NEW Australian Species of Crustacea. 

 By C. Spence Bate, F.R P> , F.L.S., etc. 



(Plates XL. and XLI.) 



The following species of Crustacea were collected and sent to the 

 British Museum by Mr. Angas, who obtained them during his so- 

 journ in Australia. Angasia pavonina is figured from a coloured 

 drawing taken of the animal, while living, by Mr. Angas ; the others 

 are from preserved specimens by the author. 



Angasia, White. 



Hippolyte similis, sed rostrum sine carina dorsali, et sine ap- 

 pendice ad mandibulam. 



Like Hippolyte, except that the dorsal surface of the carapace is 

 horizontally continuous on the rostrum, and gradually converges 

 laterally to a point, and the mandibles are without any secondary 

 appendage. 



This genus was founded by Mr. Adam White, and orally described 

 by him at a Meeting of the Zoological Society, for the purpose of 

 receiving a very pretty species that was brought from Australia by 

 Mr. Angas. 



The arrangement in this memoir differs from that of Mr. White in 

 making the form a genus instead of a subgenus. This I do, first, 

 because a subgenus appears to be both an inconvenient and an unna- 

 tural arrangement ; and second, because whenever there is any struc- 

 tural distinction, however unimportant it may appear to be to our 

 cognizance, yet it is impossible to classify such a species together in 

 a genus with others not possessing the same structure. For quick 

 detection, no doubt variation in form may be more appreciable for 

 observation than an alteration of structure ; but it stands to reason 

 that the latter, however small, must be far more important in the 

 economy of the animal's life than the former. It must also be taken 

 into consideration that we seldom find any structural alteration, how- 

 ever small, without perceiving a more or less important variation in 

 the condition of some other part of the same animal. 



This genus is closely allied to Hippolyte, from which the most 

 palpable distinction exists in the absence of the carinated ridge that 

 traverses the rostrum and the dorsal surface of the carapace, and in 

 the more important feature of the absence of the apparently insigni- 

 ficant appendages attached to the mandible. 



Angasia pavonina. (PI. XL. fig. 1.) 



A. rosfro tarn longo quam carapax, et antenna inferiore tarn 

 longa quam pars dimidia pleontis sui. 



Length 2g inches. 



This, the only species that has been found, has the rostrum quite 

 as far projecting iu advance of the eye as the carapace extends pos- 

 teriorly to it, with a deep carina upon the inferior surface, having the 

 margin furnished with four small teeth. The eye is elevated upon a 



