Mollusks. 3303 



the stems, although in one spot there is a stone bank literally swarm- 

 ing with Helix aspersa, yet they were seldom found among the stones. 

 The name being evidently a misnomer, is calculated to mislead as to 

 their habits and place of resort. 



I am glad to find the study of this interesting branch of Zoology 

 becoming more general, and I hope, ere long, we shall have lists given 

 for most of the principal counties in England. Our knowledge of the 

 range and distribution of the species here is extremely defective, and 

 the publication of these from carefully worked districts would be of 

 infinite service ; not a mere catalogue of such as protrude themselves 

 to the notice of every stroller, or may even be found in the course of a 

 morning's ramble, but the result of au attentive and diligent search in 

 every probable spot within reach of one's residence. For many are 

 only to be found at certain seasons of the year, and then only for a li- 

 mited period, and this, too, often within a very circumscribed space, 

 although at such times they may be taken in the greatest abundance. 

 Planorbis nilidus, until quite lately, I had only found sparingly, ad- 

 hering to aquatic plants ; but on taking out masses of Conferva? to 

 search for the smaller Pisidia, they were discovered to be literally 

 teeming with this Planorbis, in company with Valvata crilata. This 

 abundance, however, lasted only for about two or three weeks, when 

 they seemed to have come to maturity, and rapidly disappeared ; whe- 

 ther they migrated, or buried themselves in the mud, yet remaining to 

 be discovered. I could mention many other similar cases ; and the 

 disappointment expressed by a correspondent who has lately visited a 

 celebrated dredging locality without finding even a trace of the trea- 

 sures it was said to contain, leads one to infer that a similar proceed- 

 ing takes place among the marine Mollusca, and that a table of the 

 " dates of appearance " may be even more of a desideratum than the 

 knowledge of localities. 



The collecting and study of the land and freshwater Mollusca affords 

 by far the readiest and most convenient stepping-stone for any one 

 desirous of becoming acquainted with the several branches of Natural 

 History, and more especially for the younger class; because the haunts 

 to be visited, and the means to be adopted for obtaining them, are 

 quite in accordance with the habits and pursuits usually followed, not 

 quite so enticing perhaps at first as birds'-nesting, but after a begin- 

 ning had been fairly made, I have little doubt, judging from what I 

 have witnessed in my own family, it would ultimately become equally 

 fascinating. Besides the easy accessibility and general abundance of 

 its specimens, some of which may be found during nine or ten months 



