STAURANDERASTER ARGUS. 99 



angular, just as in a typical Metopaster. Other terminal plates are, however, 

 small and approximate to those characteristic generally of Asteroidea, The 

 specimen figured in Text-fig. 2 presents no terminal plate which has a resemblance 

 to those typical of Metopaster. In all other respects the specimens are almost 

 exactly similar to one another. 



The infero-marginalia are smooth and slightly concave in the centre. They 

 are eight in number. 



The actinal area of the disc is covered with sub-equal plates, which are four- 

 sided in the inter-radial regions and tend to become hexagonal radially. 



Locality and Stratigraphical Position. — Zone of Actinocamax quadnitus, East 

 Harnham, Salisbury. 



Remarks. — The ornament of this species is identical with that of M. uncatus. 

 The important differences between the species lie in the shape of the marginal 

 plates, the character of the terminal supero-marginalia which show their especial 

 peculiarities in all the specimens, and the ornament of the abactinal plates of 

 the disc. 



Family— PENTACEROTID^ (Gray), emend. Terrier, 1884. (See p. 76.) 



Genus— STAURANDERASTER, novum. (See p. 125.) 



12. S. aegus, n. sp. PI. XXV, figs. 6, 6 a ; PI. XXIX, figs. 8, 8 a, 9, 9 a. 



Specific Characters. — Ossicles ocellato-punctate. Surface of ossicles very 

 rarely truncate. If truncate, the flattened surface is not striated so as to simulate 

 the asteroid madreporite. 



Material. — Only very fragmentary specimens of this species are known. The 

 best preserved specimen is in the collection of Dr. Blackmore, of Salisbury, and is 

 figured on PI. XXIX. Dr. Blackmore also possesses other specimens belonging 

 to this species. Two specimens of the species are also preserved in the British 

 Museum (Nat. Hist.), and bear the registered numbers E. 5019 and E. 25GG 

 respectively. The first-named specimen was presented by Mr. W. McPherson. 

 The second specimen was originally figured by Forbes in Dixon's ' Geology of 

 Sussex,' pi. xxi, fig. 1G, as a "fragment of an Oreaster." In Part III of this 

 Monograph it was figured under my direction (PI. XXV, figs. G, G a) as Genus (?), 

 Sp. (?). I have now isolated two or three ossicles from the specimen, and they 

 are figured on PI. XXIX, fig. 9. They show that the ossicles as originally figured 

 merely present their interior aspect. The specimen E. 5019 is taken as the type. 



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