64 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 



HUDSONASTER RUGOSUS (BiUings). 

 Plate 3, fig. 1. 



Palasterina rugosa Billings, Geol. Surv. Canada, Kep. of Progress for 1853-1856, 



1857, p. 291; Geol. Surv. Canada, Can. Org. Remains, dec. 3, 1858, p. 77, pi. 



9, figs. 2a-c. 

 Palasterina rugosa Wright, Men. British Foss. Echinod., Oolitic, vol. 2, pt. 1 



(Pateontogr. Soc. for 1861), 1862, p. 27. 

 Hudsonaster rugosa Sturtz, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 



pp. 218, 224, 225. 



Original description. — "Two inches [not over 47 mm.] in diameter, 

 rays five, acute at their apices and rapidly enlarging to a breadth 

 of four lines [about 11 mm.] at the disk, which is eight lines [about 

 17 mm,] in width. The specimen shows the upper [or abactinal] 

 side of the fossil only; some of the plates are absent from the center 

 of the disk, but those which remam are very prominent in their 

 centers, and roughly ornamented by fom' or five deep crenulations 

 or furrows from near the center to the edges, producing a star-like 

 appearance resembling a half-worn plate of Glyptocrinus decadac- 

 tylus; their diameter is from one to two Imes [largest diameter 4 mm.]. 



"The rays are composed (at least the backs and sides of them) 

 of four rows of plates [due to distortion, a careful analysis shows 

 five columns] which are so very prominent that they appear to be 

 almost globular, and even pointed in their centers, the central 

 [radial] rows are the smallest [as in H. incomptus]; the first four 

 plates of the outer [supramarginal] row occupy three lines in length, 

 and of the inner [radial] rows nearly as many. Toward the point 

 of the arm all diminish rapidly in size. 



"Beneath the outer [or supramarginal] rows two others can be 

 seen [the inframarginal], which are probably the outer marginal plates 

 of the under [or actinal side], corresponding to those of Petraster 

 rigidus." 



Locality and formation.— IR^ichmondian series, Charleton formation, 

 at Charleton Point, Anticosti Island. Tw^o specimens collected by 

 J. Richardson are now in the Victoria Memorial Museum at Ottawa, 

 Canada (No. 1999). 



Remarlcs. — The same description was republished in 1858 with 

 the addition of three figures. These, and a direct examination of 

 the two type-specimens, show that this species clearly belongs to 

 Hudsonaster and that it is closely related to H. incomptus. The 

 smaller free specimen preserves a portion of the disk and parts of 

 two rays and shows clearly the presence of a single large axillary 

 plate. H. rugosus, however, attained a considerably larger growth, 

 has a greater number of plates in each column and these are described 

 as ''almost globular," while in H. incomptus the abactinal plates are 

 very convex but not globular. Then the basal supramarginal and 



