C.A. NEW YORK STATE MUSEUM 



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The integument, on the dorsal side of the disk, in the inter- 

 brachial areas' and on the rays, consists of a rather thick calcareous 

 layer, which rises to a broad node or apex in the center of the star- 

 fish, above the wide oral cavity. It exhibits a very fine sculpturing, 

 consisting of granules which are arranged in very regular radiating 

 lines. These are separated by intervals little wider than their 

 * diameter. In the section these granules appear as rods and there is 

 little doubt that they are original calcifications of the integument. 



It is in this connection interesting to note that Spencer has shown 

 that the genus Stenaster, hitherto classified with the Asteroidea, is 

 really a very primitive " ophiuroid ". and belongs to the subclass 

 Auluroidea of the Stelleroidea. Schondorf, who first clearly recog- 

 nized the composition of the rays in this class, of one layer of 

 ossicles only, gave the diagrammatic section of a ray, here repro- 

 duced in text figure 21. Spencer has furnished in his paper 

 {op. cit., p. 23) the improved diagrammatic section, here repro- 

 duced in text figure 23, which shows a thick dorsal integument 

 covering the coelom. He states, however, (p. 25) of this integu- 

 ment, that it had " few or no calcifications." He assumes its former 

 existence on theoretical grounds. As our specimens indicate, it 

 must have been well calcified in S . s a 1 1 e r i which species thus 

 verifies Spencer's conclusion as to the section of this remarkable 

 stelleroid, which on the one hand is still very close to the primitive 

 Asterozoa and on the other leads already to the Ophiuroidea. 



The specimen reproduced in plate XI, figure 1, exhibits near the 

 center, but nearer to the upper right interradius than indicated in 

 the figure, an elliptic prominence with a central depressed smooth 

 area. This node is clearly the center of the dorsal sculpture and 

 therefore not a fortuitous feature. The central depressed area 

 contains an elongate perforation which may be accidental, but 

 which, situated as it is, can not help but being quite suggestive of 

 an original opening. It is possible that Stenaster, which although 

 an auluroid, still exhibits various primitive stelleroid features, may 

 also have retained the anal opening. The latter, though undoubtedly 

 present in the Paleozoic starfishes, has never yet been clearly ob- 

 served (see Schuchert, op. cit., p. 39). In recent starfishes it is 

 reduced to a minute pore or entirely absent, as it is also in the 

 Ophiuroidea. In the primitive starfishes, owing to their descent 

 from the Edrioasteroidea I the anal opening, which migrated from 

 the actinal to the abactinal side, should be distinctly recognizable. 



1 See Bather, F. A. Studies in Edrioasteroidea, 1915. 



