Mr. W. Thompson on the British Actiniadue. 231 



two very dissimilar species. No one, I am sure, who has ever seen 

 these Polypes would imagine for an instant that they can possibly 

 belong to the same genus ; and indeed the fact that Adamsia palliata 

 secretes a horny base, an incipient polypidom, induces me to suggest 

 the necessity of forming on its characters a distinct family. I have 

 therefore constituted a genus for the reception of Actinia parasitica, 

 and withdrawing the suggested name Sagartia from the genus that 

 will now stand as Paractis, I have transferred it to this genus. The 

 genus Adamsia I at present retain under the family Actiniadce ; and 

 without entering into the question in this paper as to its proper 

 position, I would suggest that it will eventually be placed between 

 the Polypes that secrete a polypidom and those without a poly- 

 pidom. 



Of late years Adamsia palliata has so decreased in this locality, 

 that I have seen but one since the severe winter some three or four 

 years ago ; this was given me in September last by my friend Mr. 

 Bask, and is still alive and well in one of my tanks, but too valuable 

 to submit to the dissecting knife. I trust this summer to obtain 

 other specimens, when I hope to settle its proper position amongst 

 the Anthozoa. 



As regards species, I refrain from touching on that point in the pre- 

 sent paper, but purpose doing so at an early period, when a careful 

 examination of a larger number of individuals shall enable me to 

 speak with authority as to which are bondjide species and also those 

 that are merely varieties. The rage for marine vivaria has thrown 

 many useless workers into the field ; and I much fear that what 

 may possibly tend to a love of nature does not always as a matter 

 of course advance science. The improper multiplication of species 

 is a serious injury to the well-being of Natural History ; and, I must 

 admit, I should like to see a council formed of five, ten, fifty, or any 

 number of the most celebrated naturalists, and that no new species 

 or arrangement should be published without their consent being first 

 obtained. This would effectually prevent varieties and deformities 

 creeping in as species, and objects already described and known 

 being reproduced as new species, or, may be, even as new genera. 



Proposed rearrangement of British Actiniadse, with a revision of 

 the genera : — 



Anthozoa, Owen. 



Body soft, contractile, in every part symmetrical. Tentacles 

 hollow, possessing thread-cells, and in most with pectinated margins, 

 in uninterrupted circles or groups. Stomach suspended by radiating 

 mesogastric folds in an abdominal cavity. No intestine ; mouth and 

 vent generally one, placed in the centre of the upper disk, very dila- 

 table. With or without polypary ; when present usually internal. 



Without polypary. 

 Actiniadce. 



Free and solitary, or gregarious. Tentacles simple, rarelv branched 



16* 



