KEVISION OF PALEOZOIC STELLEROIDEA. 161 



which alternates with those of the supramarginal plates. The 

 latter are slightly tumid, subquadrate in outline, regular in size, 

 but decreasing gradually distally. Outside of these and margining 

 the rays may be seen a little of the inframarginalia, which bear pairs 

 of short, slender, and finely striated spines. There are from 31 to 

 33 closely adjoining plates in each one of the abactinal columns; 

 there appear to be no accessory plates of any kind in the rays. 



Disk circular in outline, somewhat tumid and covered by small 

 many-sided plates that originally appear to have been closely adjoin- 

 ing. 



Remarks. As this is the only American starfish with more than 

 five rays, it is readily distinguished from all others. The abactinal 

 arm structure is practically that of Hudsonaster, with the difference 

 that in L. labcocki the inframarginals do not project beyond the 

 supramarginals and are therefore not seen as a rule from the dorsal 

 side in the natural casts. 



Locality and formation. The holotype, an excellent specimen, was 

 found in the lower part of the Upper Devonic, near Ithaca, New 

 York, by Mrs. G. W. Babcock, after whom the species is named; 

 it is in her possession. The writer's attention was called to this 

 interesting specimen by Prof. H. S. Williams of Cornell University. 

 Some years after this starfish was described in manuscript, Clarke 

 directed attention as above cited to two others found in the Cashaqua 

 shales of the Portage in Hunt's quarry, at Interlaken, New York. 



Cat. No. 60627 (cast), U.S.N.M. 



FAMILY, unknown. 

 Genus ASTROPECTEN Link. 



The genus Astropecten is based upon living species, and it is not 

 probable that the Devonic forms are identical. 



ASTROPECTEN (?) SCHLUTERI Sturtz. 



Astropecten schluteri STURTZ, Palaeontographica, vol. 32, 1886, p. 87, pi. 10, figs. 1, 

 16, 2, 2a; Verb, naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 51, 71. 



In the roofing slates of the Lower Devonic at Bundenbach, Ger- 

 many. A single very much distorted and compressed example is 

 the basis of this species. 



Genus ATAXASTER Jaekel. 

 Ataxa.ster JAEKEL, Zeits. geol. Gesell., vol. 55, 1903, Protokol, p. 14 (106). 



Genoholotype and only species. A. pygmseus Jaekel. Ordovicic 

 (DJ, St. Benigna, Bohemia. 



Description. "A small asterid whose ambulacrals in the distal 

 parts are alternate, but in the proximal are opposite." 



Remarks. The above is all that is known about Ataxaster, and 

 for the present the genus has no value. 



