Mr. W. Clark on the Cliemnitzise. 381 



would have accompanied our mai'ch. The descriptions and 

 figures of the animals and shells are often perfection, and leave 

 nothing to be desired; I use no others, and find my doubts on 

 these points always resolved ; they have superseded every other 

 reference, and are in themselves a British conchological library. 

 The notes on each species have been thought too long ; I dissent 

 from this opinion, and think that in these difficult and often 

 diminutive objects, identity, particularly to the younger students, 

 cannot be communicated unless the delicate and minute differ- 

 ential features are pointed out. I should regret to see a greater 

 conciseness introduced. 



Whilst I am on this subject, I will venture to allude to a recent 

 publication which I have just read — I mean the ' Introduction to 

 Conchology,^ by George Johnston, M.U., who has not only given 

 his own extended experiences, but referred us to the best of 

 eveiy thing that has been written on the subject of his book, 

 affording a mass of information and malacological lore that has 

 never been surpassed, and 1 doubt much, if in the same space 

 it has ever been equalled ; the notes are truly valuable. I should 

 fail in my duty to this branch of science if I did not confidently 

 recommend to my brethren, my friends, the young student as 

 well as the experienced naturalist, not to delay the perusal of 

 this excellent work. I may truly say to the votaries of this 

 lovely science, the elegant i-esource of leisure at home, and of 

 the sea-side visit, that if they neglect the aids of such books as I 

 have alluded to, they will be left far behind by their competitors 

 who have the wisdom not to set out without these vade-mecums. 

 I propose to endeavour to dispel the clouds which envelope 

 this beautiful and interesting group, by a variety, I hope, of 

 useful prehminary obsei-vations, by many additions to my former 

 memoir on this subject, by giving a catalogue of every British 

 Chemnitzia, sweeping away the phantoms of the genus, and thus 

 establishing the means of identifying every genuine species, 

 whereby the collector will be enabled to complete his list without 

 fretting himself by endeavouring to obtain many recorded ob- 

 jects, which may as well be looked for as the philosopher's stone 

 or the perpetual motion. Without further preface, I will make 

 one or two general remarks, and then enter on some particular 

 Chemnitzian incidents, concluding with a series of short expla- 

 natory notes on every British species, whether genuine or apo- 

 cryphal, that has found its way into our various annals. This 

 review of the tribe, which I call Chemnitzia, and others of the 

 moderns term partly Chemnitzice and partly OdostomicB, will I 

 think interest and be singularly useful both to the malacologist 

 and conchologist. In vaj expose I shall show that this group, from 

 its comparative difficulty and obscurity, has long been the arena 



