1879.] MR. F. J. BELL ON THE ECHINOIDEA. 655 



instead of with the red which is so conspicuous in P. parmatus. 

 Our specimens are from New Ireland. 



PAPILIO BROWNl, U. Sp. 



Exp. 4 in. P. wallacei similis, sed paulo obscurior, anticis maculis 

 intra cellulam majoribus, ea ad basin viridissima, duabus interiori- 

 bus linece submediance angustioribus, maculis submarginalibus fere 

 obsoletis ; posticarum macula basali intra cellulam carente : 

 subtus anticis maculis virescentibus et colore purpurascente in 

 dimidio apicali absentibus ; posticis maculis basalibus viridissimis, 

 ea intra cellulam minutissima (fere obsoleta), lunulis rubris un- 

 guium analem versus majoribus. 

 We have received a single female of this insect from New Ireland. 

 The differences indicated in the foregoing description point out its 

 specific distinctness from its close ally P. wallacei. Mr. Hewitson's 

 figure of this latter species is taken from a New-Guinea specimen, 

 and accurately agrees with an example sent us by Dr. Meyer, 

 obtained by him in the same island (c/. Kirsch, Mitth. d. k. zool. 

 Mus. zu Dresden, Heft ii. p. 1 1 3). 



8. Observations on the Characters of the Echinoidea — II. 

 On the Species of the genus Tripneustes , Agassiz. By 

 F. Jeffrey Bell, B.A. Magdalen College, Oxford, 

 Zoological Department, British Museum, F.Z.S. 



[Keceived June 16, 1878.] 



(Plate XLIX.) 



It is with the greatest regret that I, in laying before the Society 

 a few observations on another genus of the Echinoidea, find myself 

 compelled at the outset to offer some remarks on the nomenclature 

 adopted by Prof. Alex. Agassiz. No one who is engaged in the 

 study of these complex and difficult forms can do otherwise than 

 feel that he owes a great deal to the acuteness of the talented 

 American naturalist ; and his work will perhaps gain in value when 

 it has been more subjected to working criticism than it has hitherto 

 been. 



As to the name which should be applied to the genus, Prof. 

 Agassiz prefers to use the name Hipponoe (Gray) in place of Tri- 

 pneustes (Agassiz) ; and he gives for this course reasons which I think 

 deserve to be reprinted : — " In retaining the name Hipponoe of Gray, 

 to which objections will undoubtedly be raised on the ground of 

 Hipponoa having been before used by Audouin ', and from the fact of 

 the name alone appearing without further indications of its connexion, 

 I am simply carrying out the principle that Hipponoe and Hipponoa 



1 Audouin & Milne-Edwards, Ann. Sc. Nat. sx (1830) p. 156. 



