ASTEKOIDEA OF NORTH PACIFIC AND ADJACENT WATERS — FISHER. 153 



Family ODOXTASTERID-E Verrill, 1S99. 



Gnathasterinse (part) Perkier, Expdd. sci. dii Travaillcur ct du Talisman, 1894, pp. 244, 251. 

 Odontasteridx YKnwLL, Trans. Conn. Acad., vol. 10, 1899, p. 201.— Fi-sher, Bull. Bur. Fisher- 

 ies for 1904, vol. 24, June 10, 1905. p. 302. 



Form similar to that of the more paxillose Goniastcridir, being either pentagonal 

 or broacUy stellate. A single reciir\-e(l, more or less hyaline median spine to eaeh 

 pair of mouth plates, or two such spines, side by side; in the latter cjise one of 

 these spines arises from near the apex of each mouth plate. An odd interradial 

 marginal plate in both series. No superambulacral ossicles. Tube feet with sucking 

 disks as in Goniasteridae. Marginal plates well developed, either decreasing regu- 

 larly in size distally, or at first increasing (as in Pentagonaster Gray) so that the 

 rays are dilated. Abactinal, actiual intermediate and atlambulacral plates as in 

 Odontaster. 



This family includes three well marked genera, two of which are extra limital. 



KBY TO THE KNOWN GENERA OP ODONTASTERID.E. 



a}. A recurved hyaline spine on each mouth plate, two side by side at each mouth angle. 



6'. Marginals decreasing regularly in size from base to extremitj- of rays Astcrodon " Perrier. 



b-. MarKiiiiils at first increasing in size; rays dilated Diplodontias b FLsher. 



a'. A recur\od hyaline spine common to the two mouth plates, therefore one at each mouth angle. 



Odontaster Verrill, p. 154. 



Renuirls. — Sladen placed his genus Gnathader in the Pentagonasterida? next 

 to Nymplmster, while Perrier relegated Asterodon, which when described included 

 both Asterodon and Griathastcr (or Odontaster as now knowm) in the .iVrchasteridae. 

 Bell in 1893, in his revision of Odontaster, followed Perrier. In 1894 Perrier placed 

 Asterodon, Goniodon, and Gnathaster in the subfamily Gnathasterina? of the Archas- 

 terida?. Tn 1899, when Verrill dismembered the .Irchasteridae, he created the family 

 Odontasterida; and placed the new group next to the Goniasterida?. 



The positive characters of the genera included in this family fidly warrant, in 

 my opinion, the step taken by Verrill, and I venture to suggest that the family is 

 nearer the Goniasteridse than to any group formerly mcluded in the Archasteridae 

 (which is now restricted to Archaster). The fact that all the species described 

 previous to Sladen's report were originally placed in goniasterid genera" further 

 bears out the imanimity of oj)inion concerning the structiu-e of the forms. Never- 

 theless Perrier and Bell believed the group to be nearer the Archasteridse, while 

 freely admitting its intermediate character. The goniasterid similarities are to be 



ofichinodermes de la mission scientifique du Cap Horn. I. StelMridea. Mission scientifique Cap 

 Horn. Zoologie, vol. 6, Paris, 1891, p. 129. 



i>Gonw(/ortPcrrier(Exped.sci.du TravaiUeureiAu Talisman, 1894, p. 244); type, Pentagonaster dila- 

 tatus Perrier. As this name is antedated, and therefore invalidated, by Goniodon C. L. Herrick, Denison 

 Univ. Scientific Laboratories, Bull. 3 (April), 1888, p. 4 (type, G. ohioensis, a mollusk), I renamed the 

 group Diplodontias in 1908 (Smiths. Misc. Coll., vol. 52, p. 89). 

 c These species were : 



Goniodiscus singularis (now Asterodon singularis). 

 Pentagonaster dilatatus (now Diplodontias dilatatus). 

 Astrognnium miliaris (now Odontaster miliaris). 

 Astrogoniiim nteridionnle (now Odontaster meridionalis). 

 Calliderma grayi (now Odontaster grayi). 



