290 TWENTIETH REPORT ON THE STATE CABINET. 



GENUS EUGASTER(n.g.). 



iGv. evye, prcestans ; acrrip, aster. "] 

 Body stellate, consisting of a central alated disc, and five long, slender, 

 somewhat flexuous rays. Disc composed of small, polygonal, tuberculose 

 or subspinose plates on the ventral side. Rays consisting of a double 

 series of alternating subquadrate ambulacral ossicles, and a series of 

 curved adambulacral plates bordering the grooves, and forming the mar- 

 gin of the ray : the outer ends overlap the edge of the next plate 

 in advance. Oral plates ten, arranged in pairs, forming the terminal 

 plates of the adambulacral ranges. Pores large, arranged in two rows in 

 each ray; penetrating the ray at the junction of the ambulacral and 

 adambulacral plates in such a manner that four different plates border 

 each perforation. Adambulacral and disc-plates bearing spines. Dorsal 

 surface unknown. 



This genus is allied to Protaster (Forbes), but differs in the struc- 

 ture and arrangement of the component parts of the ray, and in the man- 

 ner in which the pores penetrate the plates ; it also differs in the form of 

 the disc, which is not circular, but extends for some distance along the 

 rays, forming acute alations on their margins. The plates of the disc are 

 polygonal, united by their lateral faces, and not squamose as in Protaster. 

 The Genus Palasterina has "the arms a little produced" beyond the 

 disc, while in this one they are much produced. The structure of the ray is 

 in general characters similar in the two genera, but in Palasterina the 

 adambulacral plates are large and quadrangular, while in this one they are 

 subsquamiform, spiniferous and subimbricating. 



EUGASTER LOGANI (n. S.). 

 PLATE IX, FIGS. 7 & 8. 



Body stellate, with a small disc and long attenuate flexuose rays. 



Disc composed of numerous small polygonal plates with radiated surfaces : 

 the diameter, measured from the sinus to its extension on the opposite 

 ray, is about half as great as the length of the ray measured from the 

 centre of the disc. 



and the typical forms of each were specified. Mr. Salter has for some reason recog- 

 nized the Genus Pal^aster proposed by me a little earlier, but probably published 

 after that of M'Coy ; and has given the two species of Urasterella to that genus. 

 Now that there seems no reason for continuing them under that generic term, they 

 should be restored to their proper position, as indicated above. The two species of 

 Forbes must either be placed under Urasterella as proposed by M'Coy, or fall under 

 the later Genus Stenaster of Billings, Were the latter genus of my own proposing, 

 I should nevertheless return to Urasterella, and I have no doubt that Mr. Billings 



will accord with this view. 

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