364 THE VOYAGE OF H.M.S. CHALLENGER. 
Genus Marginaster, Perrier. 
Marginaster, Perrier, Bull. Mus. Comp. Zoél. Harvard, 1881, vol. ix. No. 1, p. 16; Nouv. Archives Mus. Hist. 
Nat., 2e Série, 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' 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,” 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 genericname. 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 fimbriatus, between 
the north of Ireland and Rockall. 
6. Bathymetrical range: 69 to 1360 fathoms. 
y. Nature of the Sea-bottom: Not recorded. 
Chorological Synopsis of the Species. 
Ocean. Range in Fathoms. Nature of the Sea-bottom. 
Marginaster echinulatus . Atlantic. 69 
Marginaster finbriatus . Atlantic. 1360 see vee 
Marginaster pentagonus . Atlantic. 218 sic “ioe | 
Marignaster pectinatus . Atlantic. 95 see 06 | 
1 Rapport sur les Travaux de la Commission chargée par M. le Ministre de l’Instruction publique d’etudier 
la Faune sous-marine dans les grandes profondeurs de la Méditerranée et de YOcean Atlantique, par M. 
Alphonse Milne-Edwards, Membre de l'Institut. (Extrait des Archives des Missions scientifiques et littéraires. 
Troisiéme série. —Tome neuvitme, Paris, 1882, p. 51.) 
2 Nouv. Archives Mus. Hist. Nat., 2e Série, 1884, t. vi. pl. i. 
