356 Mr. W. Clark on the Littorinidse. 



great impulse from that valuable work, f The British Mollusca/ 

 wherein the learned Professor and his coadjutor have boldly 

 broken through the trammels of the old system, and as far as 

 possible, founded the classification on natural organization, and 

 at a great expense of arduous research, though still from neces- 

 sity retaining hundreds of unmeaning and worthless synonyms, 

 expunged and weeded out a multitude of exotic species which 

 disfigured and almost choked up our indigena ; these are great 

 services, and every naturalist in this line will feel a lively satis- 

 faction, that by these aids he can now pursue a delightful study 

 agreeably to the order of nature. A new sera has commenced in 

 British malacology; it stands disenthralled from arbitrary and 

 defective dispositions, and in future will march hand in hand 

 with its elder sister, conchology. And lastly, that I may not be 

 misunderstood on the subject of the varieties, I beg to state, that 

 I consider the mention of all, very desirable and of great import- 

 ance as varieties, but not as species, and on this point I give an 

 extract from a deservedly high authority. M. Philippi says, 

 " Semper varietates sedulo notavi, hoc etiam valde necessarium 

 duxi, cum auctores qui in musaeis modo conchylia describunt, id 

 minus apte facere possint, quam ille qui centena specimina in 

 maris littore ipse colligit et observat ; sed nimium plerumque 

 colori, aliisque notis variabilibus, dignitatem tribuant, aut setates 

 diversas pro speciebus diversis sumant, sicut ex. gr. multoties 

 clarissimus Risso fecit ." This opinion is expressly given sub 

 modo, that especial care is to be taken that varieties are not in- 

 serted as species. 



It now remains by examples to illustrate and impress on the 

 minds of young naturalists the value and pressure of the prece- 

 ding observations. Perhaps a stronger case of the improper mul- 

 tiplication of species on frivolous grounds cannot be brought for- 

 ward than that of the genus Anomia, which, as I believe, only 

 contains a single British species, the Anomia ephippium, the mere 

 varieties of which have constituted the sixteen or seventeen spe- 

 cies that are consigned to our conchological annals, and are based 

 on the arbitrary and artificial distinctions of colour, the various 

 adscititious markings, and forms resulting from the substances 

 on which they are fixed, combined with the influencing effects of 

 habitat, food, and depth of water. 



I have the last summer examined and dissected 500 Anomia 

 of all forms, sizes and colours from different habitats, and in the 

 endless variety of colour and markings of this proteiform genus 

 I have not discovered a single specific character, either as regards 

 the anatomy or external organs of this genus, that would justify 

 the creation of a single species. I have now done with the Ano- 

 mia, as the learned editors of the ! British Mollusca • have, though 



