LEPID ASTER GRAYL 117 



1893. Lepidagter grayi, Stiirtz, Verhandl. nat. Ver. preuss. Rheiiil., vol. 1, pp. 52-72. 



1914. ,, grayi, Schuchert, Fossilium Catalogus, Animalia, pt. 3, pp. 5, 7, 22, 23. 



1915. „ grayi, Schuchert, Bull. 88, U.S. Nat. Mus., pp. 38, 40, 158—160. 



Material. — Five specimens of the species are known. The holotype figured by 

 Forbes is in the British Museum (Nat. Hist.) and is registered as 40215. A 

 smaller but much better preserved specimen is in the collection of the Museum of 

 Practical Geology, Jenny n Street. The third specimen is in the Dudley Museum 

 (No. 606), and the fourth in the Sedgwick Museum, Cambridge (a 717). A small 

 specimen, which I believe to be a young immature form of the species, is in the 

 Ketley Collection of the University of Birmingham. 



The Holotype. — This has been excellently figured by Forbes, who describes the 

 disc as " unfortunately so injured that its elements cannot be made out, but appears 

 to have had a framework composed of closely-set polygonal ossicles." It is, as 

 Forbes says, very difficult to make out any arrangement of the ossicles of the disc, 

 but this may be due to secondary modifications due to the old age of this large 

 specimen. The structure of the free portions of the arm is as in the Jermyn Street 

 specimen. There is one point, however, which deserves special mention. Forbes 

 describes " small polygonal intervening plates " which cover the ambulacral groove 

 between the adambulacralia. These, if present, would be comparable to the ventral 

 shields of the Ophiuroidea. Stiirtz suggests that these plates are really separated 

 ambulacralia, a conclusion supported by Schuchert (85, p. 159). There is no doubt 

 that the plates look suspiciously like extra subambulacral pieces, as they are so 

 regularly polygonal ; and I have not been able to dissect downwards, without 

 spoiling the specimen, to determine their true character. In view of the fact that 

 they are not present in any of the other specimens, one must support Stiirtz's 

 conclusion. The madreporite is plainly figured but it appears to have escaped 

 textual notice by all observers. 



The Jermyn Street Specimen (Plate VII, figs. 1—5; Text-figs. 71, 72).— There 

 are thirteen arms, orientated for the purpose of description by means of the 

 madreporite which is situate in the interradius between the arms regarded as I 

 and ii. This interradius is well preserved and is drawn together with the border- 

 ing ossicles as Text-fig. 71. The main series of ossicles can readily be identified. 

 The mouth-angle plates are large ossicles fitted with an exceptionally stout torus. 

 The adambulacralia of the arms are wide and oblong, occupying the major portion 

 of the oral surface and distally also assisting in forming the margin. Proximally 

 they are considerably modified, a prominent transverse ridge being especially 

 noticeable. The infero-marginalia in the axils of the arm are long and flat. When 

 they pass on to the arms they become rounded and globular. There is also a large 

 triangular interradial area filled in by numerous flat plates (ventro-lateralia) which 

 separate the adambulacralia of neighbouring radii. A large madreporite is in the 

 axil of the arm just exterior to the infero-marginalia. 



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