OF NEW SOUTH WALES. 2-15 



is. R. nana with its own kind, and R. avrata with its own kind, 

 as indeed they may sometimes be seen to do upon the rocks ; but 

 they do not become fertile. I say this, however, with hesitation, 

 as my observations were only continued for a few weeks, and in 

 that time the experiment could not be regarded as conclusive. It 

 would not surprise me to find that either or both can become 

 fertile, because there are many places on the coast where no species 

 can be found, except the variety now known as R. aurata. On 

 the beach by the side of Government House, Hobart Town, no 

 grown specimen of R. nana is seen, yet young individuals are just 

 as plentiful theie as elsewhere. From my observations, I hold it 

 is quite certain that the normal arrangement is for R. aurata to 

 fertilise R. nana, which latter brings forth the fry. 



How then are we to regard the names R. nana and R. aurata 

 — as synonyms, or what ] The names of species they are not ; 

 neither are they the names of varieties. Their date is the same, 

 having both been bestowed by Messrs. Quoy and Gairnard in 1834 

 loc. cit., p. 273, 276, pi. 62.) I should prefer keeping R. aurata 

 as less liable to lead into error for nana ; a dwarf is not applicable, 

 the species being by no means the smallest of the genus, and being, 

 moreover, very variable in size. The following is the diagnosis of 

 Messrs. Q. and G. with the synonomy of Crosse. 



Trochus auratus, Q. and G. I. c. Kiener, species pi. 34, /. 2 ; 

 T. melanostomus, Deshayes, 1843, in Lamarck, ed. '2, vol. 9, p. 157 

 (rec GmelinJ ; Bembicium melanostomum, Philippi 1846, in Zeits. 

 fur Malak., p. 130/ Risella lutea, R. and A. Adam*, 1858, Genera 

 vol. 1, p. 318, pi. 33, fig. 5, rec (Q. and G.J ; Crosse, Jour, de 

 Conchyl., vol. 12 f 1864), p. 233. 



Testa imperforata, conica, rugosa, subplicata, lutea, Aammidis 

 longitudinalibus fuscis ornata ; basi plana, striata. 



Messrs. Quoy and G. found the species on the rock in D'Entre- 

 casteaux Channel, whence all my specimens came. Mr. G. F. 

 Angas emotes it also as from St. Vincent's Gulf, S. Australia, but 

 the species vary there to some extent, as I shall presently notice. 

 The following is my own diagnosis from a comparison of many 

 hundred species :— - 



