364 



THE VOYAGE OF H.M.S. CHALLENGER. 



Genus Marginaster, Perrier. 



Marginaster, Perrier, Lull. Mus. Comp. Zool. Harvard, 1881, vol. ix. No. 1, p. 16 ; Nouv. Archives Mus. Hist. 



Nat., 2e Sene, 1884, t. vi. p. 229. 



Two species bearing this generic name were described by Perrier in 1881, and a third 

 species was added by the same author x in the following year. A short diagnosis of the 

 genus was first given in 1884. The descriptions of these interesting forms are unfortunately 

 so brief and general that although two of the species are figured, 2 I feel some doubt as to 

 whether all the three belong to one genus, and I have been unable to form any clear view 

 as to the scope of the genus. It is, therefore, not without some hesitation that I now 

 venture to describe a small starfish dredged during the " Porcupine " Expedition as a new 

 species of Marginaster, but its characters appear to me to accord so closely with those 

 mentioned as presented by Marginaster pectinatus, Perrier (which I presume may be 

 considered as the type of the genus), that I prefer to take this course rather than burden 

 nomenclature with what might ultimately prove to be a superfluous generic name. Under 

 these circumstances it would be premature and injudicious in me to endeavour to formu- 

 late a more complete diagnosis of the genus, on the basis of the form which I have 

 studied, until fuller information on the previously described species is available. 



Chorology of the Genus Marginaster. 

 a. Geographical distribution : — 



Atlantic : Four species between the parallels of 10° and 60° N. 



Marginaster pectinatus, in the Gulf of Mexico, off the coast of 

 Yucatan. Marginaster echinulatus, off Barbados. Marginaster penta- 

 gonus, " Talisman" dredging No. 37. Marginaster jimhriatus, between 

 the north of Ireland and Eockall. 

 (5. Bathymetrical range: 69 to 1360 fathoms. 

 y. Nature of the Sea-bottom : Not recorded. 



Chorological Synopsis of the Sp>ecies. 



1 Eapport sur les Travaux de la Commission chargfe par M. le Ministre de lTnstruction publique d'etudier 

 la Faune sous-marine dans les grandes profondeurs de la Me'diterran^e et de 1'Ocean Atlantique, par M. 

 Alphonse Milne-Edwards, Membre de ITnstitut. (Extrait des Archives des Missions scie?itifiques et litteraires. 

 Troisieme serie. — Tome neuvieme, Paris, 1882, p. 51.) 



2 Nouv. Archives Mus. Hist. Nat, 2e Serie, 1884, t. vi. pi. i. 



