Mr. J. G. Jeffreys on Chemnitzia and bthh' Mollusca. 467 



(raised by himself) as to this being a distinct species is to be 

 considered finally settled by him, and that (to use his own word^) 

 " it admits of no further discussion." / doubt much if Mr. Clark 

 ever saw typical specimens of O. turrita, Mr. Barlee's shells 

 (which I have seen) unquestionably belong to another species 

 \0. plicata), and the species in question (to which I refer the 

 striokta of Alder) is quite different. It certainly (in my opi- 

 nion) cannot be what Mr. Clark supposes, O. acuta. Several of 

 the true Odostomice will under a microscope, as I stated in a 

 former paper, be found to be finely striated in a spiral direction. 

 ' Mr. Alder's remarks on the genus established by him, and 

 adopted by the authors of the ' British Mollusca' for the recep- 

 tion of some animals and shells of a different nature from that 

 of Odostomia or Chemnitzia, and which has been (more I fear out 

 of compliment than from a sense of justice or merit) named after 

 myself, appear to be unanswered by Mr, Clark ; and I believe 

 every other naturalist supports the former in his views — 



" non nostrum est taatas componere lites." 



But with respect to the statement made by Mr. Clark, that these 

 Mollusks must be Chemnitzice, because the apical whorls of their 

 shells are reversed or folded back on the succeeding one, I will 

 endeavour to convince him by the accompanying Plate (PI. XV.), 

 that this is not the case in any of the Jeffreysiee, and that 

 he must have either mistaken the shells or laboured under some 

 optical delusion. The objects represented in this Plate (and for 

 which I am indebted to a most able and observant naturalist, 

 my friend Mr. Spence Bate) are Jeffreysia diaphana, opalina and 

 (?) GulstoneB, Rissoa parva (var. intemipta), i?.? eximia or Barleei, 

 and Odostomia plicata and Eulimoides or pallida. I ca.n vouch 

 for the accuracy of the drawings, and that they were taken from 

 fresh and not worn specimens. If Mr. Clark collected shells 

 himself, instead of trusting to a fisherman, he would I think 

 have become better acquainted with their habits and habitats 

 than to hazard the ex cathedra assertion, that " live shells, espe- 

 cially the littoral ones, are more liable to suffer from the attrition 

 caused by the tides and waves than those of the deeper zones," 

 and thereby conclude, that the apices of these shells may be 

 rubbed off so as to simulate the button-shaped apices of the 

 Rissoa. The shells in question, when found on the shore, in- 

 habit the under surfaces and crevices of stones, where no such 

 attrition could very easily take place. 



Mr. Clark seems to have made up his mind that every recorded 

 species must be found at Exmouth, — a fault which is said to be 

 common to other local collectors and naturalists. I can only in 

 this way account for his assertion, that several which he is not 



30* 



