468 Ml". J. G. Jcft'icya on Chemnitzia and other Mollusca. 



likely to have met with or seen are varieties of other species, e. y. 

 conspicua, which he refers to acuta, nitida, dubia and alba to pal- 

 lida or Eulimoides, clathrata to intei'stinda, turrita to acuta or 

 whichever other species he has by this time determined, yb?v?«os« 

 to rufa, diaphana to obliqua, affinis and clavata to acicula, and 

 truncatula to cylindrica. I am only surprised at his not being 

 equally assured that glabrata is identical with some other of the 

 Exmouth species. 



While I fully acknowledge the services which Mr. Clark has 

 rendered to science in this department of natural histoiy, I can- 

 not forbear sharing in and expressing the regret which is enter- 

 tained by so many naturalists, that he is endeavouring unneces- 

 sarily to renew the confusion which once existed in this confess- 

 edly difficult gi'oup of Mollusca ; as well as that his opinions are 

 so positively and almost dogmatically enounced ; because after all 

 the distinction of species must be to a great extent matter of 

 opinion and dependent on the peculiar views of the writer. His 

 honesty of purpose is undeniable ; but he is, as well as others, 

 liable to mistake. 



I quite coincide with him in the just tribute of acknowledge- 

 ment which he has paid to my friend Mr. Barlee for his inde- 

 fatigable labours and researches. 



I will now add a few notes of additional localities which have 

 lately occui-red to me, as well as with respect to some of the 

 species : — 



O. pallida [Eulimoides, Bell) . The typical specimen in the 

 British Museum marked " Turbo pallidus, Mont." appears to be 

 a worn shell of Rissoa parva, var. interrupta. 



O. notata. This is certainly not a variety of the last, but spe- 

 cifically identical with the shells found by Mr. Barlee in Zetland, 

 and doubtfully referred by the authors of the ' British Mollusca ' 

 to the Rissoa glabrata of Miihlfeldt. In Mr. Barkers specimens 

 however (several of which are now before me) the spiral striae 

 have become obliterated by attrition. It is allied to Rissoides. 



O. Rissoides. Oban (Dugald M'Kenzie). 



O. nitida. The Exmouth shells which Mr. Clark referred to 

 this species, and which I have had an opportunity of carefully 

 examining and comparing, are only a variety of Rissoides. 



O. acuta. Sark, Mr. Barlee. If Mr. Clark knew this species 

 so many years ago, as he states, it is strange that specimens of 

 it should have been placed by him on the same tablet and mixed 

 with unidentata in his collection, which I purchased of him. 

 Those were his only specimens. 



