PAJIT 5 A MONOGRAPH OF THE EXISTING CRINOIDS 127 



iinder suitable conditions for some distance southward along the coasts of Scotland and 

 England and in deep water in the Irish Sea, or it is merelj^ one of the numerous varieties 

 of bifida stabUized by the relatively uniform conditions of temperature, salinity, etc., 

 imder which it hves in deep water and to the northward. 



As Koehler says, moroccana is probably only a southern variety of bifida. Stunted 

 English specimens sometimes approach it very closely. Where the dividing line should 

 faU, if in fact there be one, remains to be determined. 



It may well be that duebeni and moroccana are identical, as affinned by P. H. 

 Carpenter; they are certainly very close to each other. 



History. — Linne in 1758 included the species of Antedon, together with the other 

 comatuhds known to him and the starfishes and ophiurans in the genus Asterias. 



In 1811 de FreminviUe created the genus Antedon, the type species, A. gorgonia, 

 being based on a specimen which he found on the bottom of a ship at Havre. Though 

 this species is not now known from Ha\Te it undoubtedly occurred there in de Fremin- 

 viUe's day, and there is no reason whatever for considei'ing Antedon gorgonia anything 

 else than the species now known as bifida. Indeed Bosc wrote in 1816 that Antedon 

 "a pour type I'etoile rosacee de Linck, tab. 37, fig. 66, qui est la Comatule mediter- 

 raneene de Lamarck." But Lamarck thought otherwise, and in the same year with- 

 out any comment or explanation he placed A. gorgonia in the sjmonymy of Comatula 

 carinata, a new species which he described from Mauritius. P. H. Carpenter accepted 

 this determination, believing that the individual might have been brought to Havre 

 on the bottom of the ship, which is in the highest degree improbable. 



In 1815 Dr. W. E. Leach created the genus Alecto (type species A. horrida, inde- 

 terminable) to which he assigned all the comatulids known to him. The forms which 

 he knew of, and which are now gi-ouped in Antedon, were included in his Alecto europaea. 

 In 1816 Lamarck erected the genus Comatula (type G. Solaris), which, like Leach's 

 genus Alecto, included all the comatulids with which he was acquainted. 



For many years the names Alecto or Comatula, more frequently the latter, were 

 used to designate all comatulids, and Antedon was entirely forgotten until it was resur- 

 rected by Ltitken and by Norman in the 1860's, and thenceforth gradually came into 

 general use. 



The reinstatement of the generic name Antedon raised a question as to its origin; 

 this was settled by Mr. T. R. R. Stebbing in 1877 who at the same time suggested 

 the emendation "Anthedon." 



The first revision of the genus Antedon, considered as the equivalent of Alecto 

 or Comatula, that is, as including aU the unstalked crinoids, was published by P. H. 

 Carpenter in 1879. He removed from the genus all those species in which the mouth 

 is excentric and which have a terminal comb on the oral pinnules, placing these in 

 the genus Actinometra (J. MiiUer, 1841, type species A. imperialis=Comatula Solaris 

 Lamarck, 1816, which is the type of Comatula) and leaving in Antedon those forms 

 with a central mouth and no comb on the oral pinnules. 



Antedon was not further restricted until 1907. Other comatulid genera were 

 described by Semper {Ophiocrinus, 1868) and by P. H. Carpenter {Promachocrinus, 

 1879; Atelecrinu^, 1881; Eudiocrinus, 1882 [replacing Ophiocrinus Semper, preoccupied]; 

 and Thaumatocrimis, 1884), but all these were based upon new species considered as 

 falling bej'ond the scope of Antedon. 



