Report on the zoological collections made in the Indo-Pacific Ocean ...

;MOLLUSCA. 61The L. Jcevls of Reeve is also L. viaiir'itiana, and quite distinct fromthe L. Icevis of Philippi (?. c. vol. iii. p. 10, pi, 6. fig. 6), which isalso from the Mauritius. L. unduJata of Gray is also considered avariety of L. mauritiana by Mr. Tenison-Woods (l. c. p. 72) ; buthere I think he overstrains the power of variation. Besides thedifference in form and colour, the violet columella and sculpturereadily distinguish that shell. In adopting the Lamarckian nameL. ccfndescens, even supposing the Mediterranean and Australianshells were the same species, I think Mr. Tenison-Woods is wrong,considering what is said upon this point by Philippi (op. cit. vol. ii.p. 166), Hanley ('Ipsa Linnsei Conchylia,' p. 326), Jeffreys, andothers.63. Risella lutea.Trochus luteus, Quo)/ Sf Gaimard, Voij. ^Astrolabe,'' vol. iii. p. 271,pi. 62. figs. 8-11 ;'Kiener, Coq. Viv. pi. 38. fig. 2.Trochus cicatricosus, Jonas, rhilipprs Ahbild. pi. 2. fig. 2.Bembiciiim hiteum, Philippi, Zeitsch. Mnl. 1846, p. 132.Risella lutea, Philippi, Kiider's Con.-Cah. p. 4, pi. 1. figs. ], 2.Risella kielmannseggi, Zelehor, J^erhandl. zool.-botan. Gesellsch. Wien,1866, vol. xvi. p. 913 ;Voy. Novara,' ' pi. xi. figs. 11 a-d.Hah. Port Jackson, Port Denison, Port Curtis, and Port Molle(Coppinger).This genus has been suppressed by Mr. Tenison-Woods (Proc.Linn. Soc. N. S. Wales, 1879, vol. iii. p. 61); but, in my judgment,it may be retained with advantage as distinct from Littorina. TheTrochoid form and flattened base of the species is not approached inthat genus, and the character of the columella is very different.According to Mr. Tenison-Woods there is but one species ot Risellain Australia (H. melanostoma of Gmelin), under which name heincludes fifteen varieties or species, which have been named anddescribed by Lamarck, Quoy, Gray, Philippi, and others.Although the separation of many species or constant local formsseems impossible, we must not therefore ignore their existence.Riaella bruni is a South-Australian shell, and does not attain anything like the size of several of the other species, e. g. R. nana,R. mdanostoma, and R. imhricata. Although it might be possibleto get together an immense series of specimens which would unitestep by step the two most extreme forms, nevertheless the R. hruniwould still remain the small species from South Australia, and theother, the R. imhricata from Sydney, Port Stephens, &c., would alsobe recognizable as such.I am far from admitting the validity of all the described speciesbut there are some, I think, which may be retained, at all events,with conv.'nience. It is not my intention now to discuss this subjectfurther, but, in conclusion, will call attention to Philippi's monographof the genus, w^hich has been altogether overlooked by Crosse(Journ. de Conch. 1864) aud by Tenison-Woods ; it was publishedin 1853 in Kiister's Conchylien-Cabinet,' and 'contains the following