ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS FISHER. 105 



be SO wide at base of ray, judginji by figure. The paxillae are slightly larger in 

 gilberti and the papulu; probably not so numerous, there being rarely six about 

 the plates, this being the rule in deinonfitrans. There are a few other minor differ- 

 ences. \Aniether demonstrans can be retained after a series of gilberti is dredged 

 remains to be seen. I think it probable that the former will bo found to be iden- 

 tical with the latter, although at j)resent the two forms appear doubtfully distinct. 



Family LUIDIID.E Verrill, 1S99. 



Luidiinx Sladen, Challenger Asteroidea, 1889, pp. 175, 244. 



Luidiidx Verrill, Trans. Conn. Acad., 1899, p. 201.— Fisher, U. S. Fish Comra. Bull., 1903, 



pt. 3, 190U, p. 1031. 

 Astropectinidx (part) Gray, 1840, and succeeding authors to Verrill. 



Phanerozonia near the Astropectinidse, but without anus, intestine, or intes- 

 tinal cceca; superomarginals aborted, represented by paxills'; iuferomarginals, 

 adambulacrals, and actinal intermediate plates forming regular transverse series, 

 the first two being correspondent in number; papulae compound, the extremity 

 forming a tuft of papillae. 



Remarks. — Sladen places the PlatastericLs"- of Gray m tliis group. There are 

 several morphological features of importance concerning which we have no infor- 

 mation. Gray's description directly contradicts Sladen's statement, but the 

 former, judging by figures, is evidently inaccurate and misleading. He says, for 

 instance, that there are no marginal plates. The correspondence in position of 

 actinal, adambulacral anil inferomarginal plates is the only feature which Plata- 

 steries has in common (according to descriptions) with Luidia. But the absence 

 of an intestine and ccecum, and the character of the papulae are more imj)ortant, 

 I think. Sladen states that PIatasteria.s has superomarginals, so that the genus 

 may really belong in the Astropectinidse near Ctenophoraster. Until definite infor- 

 mation is forthcoming it may remain provisionally a member of tliis family, although 

 I think that it will ultimately be placed in the Astropectinida;. The presence of 

 superomarginals certainly would exclude the genus from the Luidiidae. If, how- 

 ever, Plafasterias lacks an intestine and coecum, and has papulre similar to those of 

 Luidia, then the feature of the superoniarginal plate would be outweighed, and 

 should be dropped from the family diagnosis. At present, however, there is no 

 evidence upon which to base a conclusion. 



Genus LUIDIA Forbes. 



Luidia P'orbes, Mem. Werneriau Soc, vol. 8, 1839, p. 123. Type L. /ragilissima Forbe8=L. 



CT7wris (Philippi). 

 Ucmicnemis Muller and Troscrel, Monat.sbcr. Akad. \Vis.«. Berlin, .Vpril, 1840, p. 105. 



Type, L. ciliaris (Philippi)). 

 Pelalaster Gray, Apn. and Mag. Nat. Hist., vol. 6, 1840, p. 183. Type, /". hardwichii Gray. 



Diagnosis. — Rays five or more, long, usually narrow, and depressed; disk 

 small; abactinal surface covered with true paxilhe, frequently in regular longi- 

 tudinal rows at sides; superoniarginal plates paxilliform, similar to adjacent 



o Proc. Zool. Soc, 1871, p. 130, pi. 9 (Tehuantepec, Mexico). 



