Mr. W. Clark on the Littorinidae. 353 



between Professor Forbes and myself. I have no copies of my 

 letters, for it has always been an irksome task to me to copy 

 what I write ; I trust to memory ; and if I have misdated any 

 point, I humbly submit to correction. As Professor Forbes's 

 letter is strictly malacological, I feel confident, from his well- 

 known liberality, that he will not consider an apology necessary 

 for the insertion of the following extract : — 



" West Lulworth, near Wareham, Dorset, Nov. 1 849. 



" I should like to know what opinion you have come to re- 

 specting the specific value of the forms of the Littorina you 

 enumerate. For my part I can only recognize Littorina littorea, 

 L. petraa, L. neritoides and L. rudis. I am in doubt however 

 whether L. jugosa should not also be held distinct." 



Being in a position to answer decisively, I wrote to the effect, 

 that having carefully examined nearly all the animals of the va- 

 rieties termed by authors L. tenebrosa, L. jugosa, L. zonaria, 

 L. rudissima, L.fabalis, L. neglecta, &c, I found them to be 

 identical with each other, and mere varieties of L. rudis, and 

 consequently that that portion of the genus Littorina consisted, 

 agreeably to his views, of only L. littorea a d L. rudis-, I however 

 added, that I believed the Lacuna, not excepting L. crassior, were 

 confined to one or two species. As the genus Littorina has long 

 been the depot of many of its varieties improperly promoted 

 to species, it occurred to me that a good opportunity offered 

 itself for making a few remarks, with the view of checking, if pos- 

 sible, this inconvenient practice, by pointing out the great detri- 

 ment that resulted to science from the fabrication of species on 

 insufficient grounds. I have been wishing for an apt opportu- 

 nity to emit my paper, which only occurred in the April Number 

 of the 'British Mollusca/ wherein malacologists will observe 

 that Professor Forbes with singular coincidence corroborates 

 with his views, mine, written many months ago, from actual ex- 

 amination of the animals. Though the learned Professor has 

 admitted into his work varieties that have not the slightest pre- 

 tensions to be styled species, for the sake of exciting further in- 

 vestigation of them, yet in page 52 of bis summary of the Litto- 

 rina, he boldly and emphatically repudiates all paternity with the 

 pseudo-species. He says — 



" In the preceding account of the Littorina several are de- 

 scribed as species which many of our ablest naturalists regard as 

 varieties, whilst others are considered as varieties which some 

 hold to be worthy of specific rank ; our conviction is, that the re- 

 sult of a completed knowledge of this genus would be a reduction 

 in the number of true British species. Taking the most perma- 

 nent features of the animal and its shell as our guide, we are 

 Ann. $ Mag. N. Hist, Ser. 2. Vol. v. "23 



