112 Mr. A. A 1 cock on 



which last are often quite smooth and unarmed ; (iv.) the 

 anal aperture is very distinct. 



This suhgenus sliows an interesting series of gradations 

 between Zoroaster^ "Wyvillc TJiomson, and Cnemidaster^ 

 Sladen. At tlie true Zoroaster extreme is Zoroaster (jiJesii^ 

 witli all tlic plates spinate and armed, with numerous pedi- 

 ccllariw, and with a broad ambulacrum and four rows of tube- 

 feet. Near the Cnemidaster extreme comes, as Mr. Sladen 

 has already pointed out, Z. Sigsheei, with the abaetinad plates 

 smootli and unarmed and only tlie actinad plates spinate, with 

 few pedicellariw, and with crowded tube-feet which only in 

 the basal part of the ray are quadriserial. "While between 

 the two come (i.) Z. squameus, with the abaetinad plates 

 granular or quite smooth and their armature reduced to one 

 deciduous spinelet, and (ii.) Z. zea, in which the abaetinad 

 plates are quite smooth and unarmed and the pedicellariaj 

 reduced in size and number. 



Family Pterasteridae. 

 JMarsipaster, Sladen. 



45. Marsipaster Mrsutus, Sladen. 



Marsijmster hirsutus, Sladen, * Challenger ' Asteroidea, p. 487, 

 ]d. IxxA-iii. figs. .3 find 4, pi. Ixxix. fiors. 4 and 6 ; and in "Wood- Mason 

 and Alcock, " Indian Deep-sea Dredging," Ann. & Mag. Nat. Hist., 

 Dec. 189], p. 437. 



Bay of Bengal, 1997 fathoms, Glohigerina-oozo. and 

 pumice. 



Hymenaster, Wyville Thomson. 



46. Hymenaster nohilis^ Wyville Thomson. 



Hymenaster nohilti<, Wy^nlle Thomson, Jomn. Linn. Soc, Zool. 

 vol. xiii. p. 7.3, fig. 11; Sladen, 'Challenger' Asteroidea, p. 49.5, 

 pi. Ixxxvii. figs. 1-3 ; and Wood-Mason and Alcock, " Indian Deep- 

 sea Dredging," Ann. & Mag. Nat. Hist., Dec. 1891, p. 438. 



Bay of Bengal, 1748 fathoms, Glohifjerina-ooze, and 

 pumice. 



Family Echinasteridae. 



Cribrella, Agassiz, Forbes. 



47. Cribrella prcestans^ Sladen. 



CriJjrella jjrastans, Sladen, 'Challenger' Asteroidea, p. 54">, ])I. xcvi. 

 fig. 7, ])1. xc\iii. figs. 7 and 8. 



Four specimens from the Andaman Sea, 240 to 480 



