440 MR. W. p. SLADEN OjS" THE ASTEKOIDEA 



The apical system is moderately large, with the anal margin 

 closely tuberculated ; the genital apertures are very large and 

 round, and the plate bearing the madreporiform body much larger 

 than the others ; the ocular plates are stout and carry numerous 

 tubercles, one being placed on each side of the aperture. Three 

 specimens furnished the following measurements : — 



A. B. C. 



millim. millim. millim. 



Diameter 17 14 14 



Height 11-75 8-3 9-1 



Actinostome 7 6 6 



EcHiNAis'THirs TESTUDiNAEiFS, Gray. 



1851. Echinanthus testudinarius. Gray, Proc. Zool. Soc. Lond. p. 35; 



et Cat. Echinida (1855), p. 6, pi. i. fig. 1. 

 1851. Echinanthus australasise, Gray, Proc. Zool. Soc. Lond. p. 34, 



et Cat. Echinida (1855), p. 5, pi, i. fig. 2. 

 1854. Ciypeaster tumidulus, Milller, Bau d, Echin. p. 90. 

 1866. Ciypeaster testudinarius, v. Martens, Wiegm. Archiv, Jahrg. 



32, i. p. 170. 

 18/0. Ciypeaster speciosus, VerriU,Silliman'sJourn. p. 95. 



CoU. St. John : lat. 33° 14' N., loDg. 128° 55' E., west coast of 

 Nip on, Korean Straits, 40 fathoms. 



EchinajSTthus testudhstaeius, Gray. 



This Clypeastroid is distinguished by the form and height of 

 test, with its deeply impressed and gradually sloping actinal sur- 

 face and large actinostome ; whilst the shape of the ambulacral 

 petals, the thickened margins of the test, and its small and widely 

 spaced tubercles are further characteristic of the species. 



The superficial resemblances which exist between certain forms 

 of -£/. testudinarius and Ciypeaster rotundus, A. Ag., are remark- 

 ably close ; the association, however, of their comparative differ- 

 ences with structural characters of considerable importance is 

 very constant, and suflS.cient to warrant full recognition in specific 

 determinations. 



(Cltpeasteoid) sp. ? juv. 



Coll. St. John: lat, 34° 8'N., long. 126° 24' E., Korea, 24 

 fathoms. 



A small Fibularia-YikG Echinoid measuring 6'5 millims. in 

 length, which is in all probability the young stage of a Clypeas- 

 troid ; but to which special form it belongs it would obviously be 

 very hazardous to determine from such limited material, in the 



