22 F. Chapman : 



The original specimens were from Flemington, and they are 

 incorporated in the collection at the British Museum (Nat. Hist.), 

 London. On account of the peculiar structure of these specimens, 

 Gregory subsequently transferred the species to a new genus, Sturt- 

 zura, making it the genotype, the genus also including the Protaster 

 leptosoma of Salter.^ Tlie numerous specimens of P. brisingoides 

 in the National Museum, Melbourne, having afforded clearer 

 data as to arm-structure tlian was possible when the original 

 specimens were described in London, this fresh evidence neces- 

 sitates a somewhat different interpretation of the arrangement 

 and form of the ossicles on the ventral surface, and restores the 

 species to its original genus. As a typical Protaster, this fossil 

 has more or less boot-shaped ambulacral ossicles, closely ap- 

 proaching those of P. biforis, Gregory.^ In consequence of this 

 determination Sturtzura leptosoma may now be considered as the 

 type of the genus. 



The third form now described is an elegant little species 

 closely related to Sturtzura leptosoma, and which I have named 

 on this account S. leptosomoides. 



DESCRIPTION OF THE SPECIMENS. 



Class — Ophiuroidea. 



Fam i] y — Frotasteridce. 



Genus — Protaster, Forbes, 1849. 



Protaster bpisingoides, Gregory. 

 (PI. VL, Fig. 2; PI. VIIL, Fig 2). 



Protaster brisingoides, Gregory, 1889. Geol. Mag., 

 dec. iii., vol. vi., p. 24, woodcuts, figs. 1-4 

 (p. 25), 



Sturtzura brisingoides, Gregory, 1897. Proc. Zool. 

 Soc. (for 1896), p. 1034. 



1 Proc. Zool. Soc. Lend. (1896), 1897, pp. 1034, 1035. 



2 Proc. Zool. Soc. (1896), 1897, p. 1033, fig. 3. 



