REPORT ON THE CRINOIDEA. 73 



i.e., at the interbasal sutures, immediately beneath the middle points of the first radials. 

 The latter have exceedingly high muscle-plates projecting inwards ; but their dorsal 

 surface is barely half as long as that of the second radials. These are nearly square, but 

 deeply incised to receive the strong backward projections of the axillaries, which are 

 roughly rhombic and slightly wider than long. 



First brachials well separated laterally, with the inner sides much shorter than the 

 outer ones, and the distal edge much incised to receive the strong backward projections 

 of the quadrate second brachials. The following joints have markedly unequal sides, 

 with a syzygy in the third or fourth, and again in the fifth, sixth, or seventh brachial. 



Disk almost naked, 4 mm. in diameter. Mouth somewhat excentric and surrounded 

 by a large peristome, immediately behind which is the anal tube. Brachial ambulacra 

 close down upon and between the muscular bundles. Skeleton light brownish-white. 



Locality.— Station 174c, August 3, 1874; lat. 19° 7' 50" S., long. 178° 19' 35" E.; 

 610 fathoms ; coral mud ; bottom temperature, 39° F. One mutilated specimen. 



Remarks. — This type differs from the other two species of the genus in the greater 

 squareness of the second radials, and in the curious relation of the basals to the centro- 

 dorsal. They are of uniform height, as in Ateleerinus cubensis, but are not in contact with 

 the centro-dorsal at the interradial angles of the calyx, being separated from it on the 

 exterior by a gap which is filled up by perisome (PI. VI. fig. 5). Apart from its 

 purely morphological importance, this Pacific species is also interesting as showing the 

 wide distribution of the genus ; and it is the only one of the three which is known as yet 

 to extend below the limit of the continental line (500 fathoms), though each of the others 

 has been dredged below 400 fathoms. 



*& v 



Genus 3. Eudiocrinus, P. H. Carpenter, 1882. 



1868. Ophiocrinus, C. Semper, Archiv f. Naturgesek., 1868, Jalirg. xxxiv. Bd. i. p. 68. 



1869. Comatula (Ophiocrinus), P. de Loriol, Denksckr. d. allg. Schweiz. Gesellsch. f. d. ges. Nature"., 



1869, Bd. xxiii. p. 57. 

 1879. Ophiocrinus, P. H. Carpenter, Proc. Roy. Soc, No. 194, 1879, p. 385. 

 1879. Ophiocrinus, P. de Loriol, Monographie des Crinoi'des fossiles de la Suisse, Geneva, 1877-79, p. 277. 



1882. Eudiocrinus, P. H. Carpenter, Journ. Linn. Soc. Lond. (ZooL), 1882, voL xvi. p. 493. 



1883. Eudiocrinus, E. Perrier, Comptes rendus, 1883, t. xcvi. No. 11, p. 725. 

 1886. Eudiocrinus, E. Perrier, Les Explorations sous-marines, Paris, 1886, p. 275. 



Definition. — Centro-dorsal and calyx like those of Antedon; but the radials bear the 

 brachials directly without the intervention of axillaries, so that there are only five 

 undivided arms. Mouth central. Sacculi abundant, scanty, or absent altogether. 



Remarks. — The genus Ophiocrinus was established by Semper in 1868 for an elegant 

 little Comatula with five undivided rays, which he had discovered in the Philippine 

 Islands ; and in the following year a fossil species was described by de Loriol from the 



(ZOOL. CHALL. EXP. PART LX. 1887.) Ooo 10 



