24 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



species, the Decempeda cornubiensium of Llhuyd, or the Antedon bifida as now known ; 

 and in 1783 Retzius carefully redescribed the Linnean types of Asterias -pedinata 

 and A. multiradiata, at the same time addmg to science a new species from the 

 American side of the Atlantic, Asterias tenellu, the Hathrometra tenella of to-day. 



Bnigidro, in the "Encyclopedic m6thodique" (1792), republished the figures of 

 comatuliils given by previous authors. 



Toward the end of the eightoenth century, Pennant, Forster, and Latham and 

 Davis, in the various editions of the "Faunula Indica," included both the Linnean 

 species as given by that author and on his authority, being able to add no original 

 matter of their own. 



Speaking solely with reference to the Linnean system of nomenclature, de 

 Fr^miiivillo took the first step hi the recognition of the comatulids as a group dis- 

 tmct from the other sea stars; in a short paper published in ISll he proposed the 

 genus Antedon for the common west European species {A. bifida), a specimen of 

 which he had found in a dry dock at Havre, adhering to the growth on a ship's 

 bottom. He made no attempt to elucitlate the two Lhmean species, or any others 

 previously known, in connection with the new one he described (A. gorgonia), nor 

 diti he go further than to show ui what way it differed from the ophiuroids. 



Simultaneously Lamarck had become dissatisfied with the heterogeneous 

 character of the Linnean genus Asterias, and m the following year (1812), in the 

 second volunio preliminary to his great work on the invertebrates, he suggested the 

 vernacular name "Comatule" (though without diagnosis) for the comatuUds, which 

 he latmized and formtUly described in 1816 as Comatula, assigning to his new genus 

 eight species, seven of them new, and overlookuig the Asterias tenella of Retzius. 



But in the meantime (1815) WiUiam Elford Leach had slipped in with his new 

 genus Alecto, covering the same ground as Lamarck's Comatula, to which he assigned 

 three species, all of which, as well as the genus itself, were very poorly diagnosed. 

 Leach's new species were based upon specimens then in the British Museum; he 

 made no reference to any other worker and, as his types have since been lost, we 

 do not know for certaui (except in one case by a fairly reasonable inference) what 

 his species were. As given by himself the three species are : 



Alecto horrida ? 



Akclo europa'a Anledon bifida. 



AUcto carinata (most probably) Tropioinelra, sp. 



It is important to scrutinize carefully Leach's arrangement in order to determine 

 the availability of Alecto as a generic name. AU subsequent authors, for instance 

 Schweigger in 1819 and Miiller in 1840, have accepted Alecto horrida as the repre- 

 sentative s|iecies of the genus. Alecto europsea is the same as the Antedon gorgonia 

 of De Fr^minville, and is therefore the type of Antedon, 1811 ; moreover, it is also 

 the same thhig as the Ganymcda pulcheUa of J. E. Gray, 1834, which is the type of 

 the genus Ganymeda. Alecto carinata is possibly the same as the Comatula carinata 

 of Lamarck, 1816, which is the type of the genus Tropiometra, 1907; this process of 

 elmimation thus leavmg Alecto Tiornda as the type of Alecto. Alecto liorrida is quite 

 unidentifiable, and therefore Alecto is unavailable as a generic name among the 



