REPORT ON THE CRINOIDEA. 103 



2. Lower joints of genital pinnules uniformly expanded. 



(a) First radials concealed; less than twenty cirrus-joints. 



(1) Calyx and arm-bases bluntly spinous; First pinnules 



almost flagellate with twenty joints or more, . 15. tuberosa, n. sp. 



(2) Calyx and arm-bases smooth ; first pinnules more 



styliform, of about fifteen joints, . . . 16. parvipinna, n. sp. 



(b) First radials visible; over twenty cirrus-joints, . . 17. flexilis, 1 n. sp. 

 b. Pinnules of tenth and following brachials have the lower joints as long as 



or longer than wide, and no extensive plating over the genital glands, 18. aculeata, n. sp. 

 B. Pinnule-ambulacra not plated. 



I. Two radials visible; arm-joints short. Stoutest pinnule on sixth brachial. 



Cirrus-joints long and smooth, . . . . . .19. denticulata, n. sp. 



II. Three radials visible; arm-joints long. Stoutest pinnule on second brachial. 



Cirrus-joints short and carinate, . . . . . .20. pusilla, n. sp. 



1. Antedon longicirra, n. sp. (PL XVII.). 

 $pec ific formula — A. — • 



Description of an Individual. — Centro-dorsal somewhat conical, bearing about 

 twenty cirri. These are enormously long (80 mm. or more), and consist of about eighty 

 segments, the lower ones of which are longer than wide. The middle joints are slightly 

 compressed laterally, and gradually develop a dorsal keel, which becomes rather large 

 in the shorter terminal joints, but is much reduced in size towards the end, and the 

 terminal claw is very small. 



The ends of the basal rays are just seen above the centro-dorsal and the three radials 

 are visible, all rather long. The first two are oblong and the third pentagonal. The 

 axillaries and the first two brachials have sharp lateral edges and flattened sides ; all the 

 radials and the oblong first brachials are very convex, the centre rising to form a sharp 

 tubercle. Ten arms, of over one hundred joints, the lower ones triangular, but wider 

 than long, and gradually becoming carinate so as to develop a forward projecting dorsal 

 spine. Beyond the thirtieth joint they become laterally compressed and begin to overlap. 

 This is reduced again in the last few joints, which diminish rather rapidly in size. 



Syzygies in the third and eleventh brachials, and afterwards at intervals of four to 

 six joints. 



The pinnules are all stiff and styliform, consisting of elongated cylindrical joints. 

 The second pair are considerably longer than the first, which are relatively small. The 

 disk and ambulacra are well plated ; but the side plates and covering plates are not fully 

 differentiated on the pinnules. Sacculi very rare, or absent altogether. 



Colour in spirit, — light whitish-brown. 



Disk about 7 mm.; spread about 20 cm. 



Locality. — Station 192, September 26, 1874 ; near the Ki Islands ; lat. 5° 49' 15" S., 

 long. 132° 14' 15" E.; 140 fathoms; blue mud. One specimen. 



1 This is also a bidistichate species. See p. 217 and PL XLII. 



