4, ME. P. ir. CAEPENTER ON THE GENUS ACTINOMETEA. 



De Frcmiuville's specimen was found on the keel of a vessel which had come from a 

 warm climate ; it had ten arms and twenty cirrhi, and was named by him Antedon (jor- 

 gonia. He gave no further description of it, but simply referred to the figure of Stella 

 decacuemus rosacea, Linck, in the ' Encyclopedic Mcthodique ' ^ which represents the 

 ordinarv European Comatida rosacea, as it is now called. 



This species, however, is not identical with De Ereminville's Antedon gorgoniu, which 

 was referred by Lamarck - to his Comutula carinata, under which name he described 

 some specimens brought by Peron from the Isle de France. Nevertheless the two 

 species resemble one another in some important points, viz. the presence of ten arms, 

 of a central or subccntral mouth, and of an excentric anal tube. 



In 1815 Leach ^ rescued the three genera contained in Liuck's classis Crinitce 

 from the confusion of the Linnean genus Astevias, and united them into one genus, 

 Alecto, comprising three species, viz. Alecto em-opaa ( = Decacnenms rosacea, Linck), 

 Alecto horrida {= Capnt-IIediisce, Linck, or Asterias multiradiata, Linn.), and Alecto 

 carinata (which seems to have been tlie same as De Ereminville's Antedon gorgonia). 



Leach defined Alecto as having the " os inferius, irregulare," a description W'hich would 

 suit equally well either for the true mouth or for tlio anal opening, though perhaps 

 more ap^dicable to the former. He seems, however, like his predecessor De Ereminville, 

 to have regarded the mouth as situated at the extremity of the anal tube ; for in the 

 explanation to Schweigger's figure' of Leach's specimen o^ Alecto horrida the latter is 

 described as the " rohrenformig hervorstehender Mund." It is obvious, therefore, that 

 we cannot make any use for systematic purposes of the definitions oi Antedon and Alecto 

 as "-iven bv Leach and De Ereminville respectively, as far as the position of tlic mouth 

 is concerned. 



Schweigger's figure of the disk of Alecto horrida shows clearly enough that the five 

 trunks of the ambulacral grooves converge towards the centre of the disk, as in Antedon 

 rosacea {Alecto europcBa, Leach), Elate I. fig. 1. Leach's Alecto horrida was therefore 

 a true Antedon in the modern sense of the term, although belonging to that division of 

 the o-enus in which the repetition of the bifurcation of the ten primary arms is carried 

 to a great extent. 



(§ 4) Leach was apparently unacquainted with the memoir of Ereminville ; but the 

 same was evidently not the case with Lamarck (181G), who, like Leach in the previous 

 year, united Linck's three genera into one, to which he gave the very appropriate name 

 Comatula^. His .definition of the genus differs but little from that given £or Antedon 

 five years previously by De Ereminville, whose original specimen Lamarck seems to have 

 examined; and it is difficult to see wliy he did not adopt the name Antedon to designate 

 the "-cnus, which, like Leach and De Ereminville, he clearly distinguished as belonging 

 to a diilerent type from the Asteridae, Ophiuridae, and Enryale. 



' Partio de3 Vers, pi. 42. fi<;. 0. ■ Tom' cit. p. 534. 



' Zoological Miscellanies, vol. ii. p. 01 : London, 1S1.5. 



* Beobacht. auf naturhistorischen Eeisen, p. 66, and Taf. iv. fig. 42 : Berlin, 1819. 

 5 Tom. cit. p. 530. 



