REPORT ON THE CRINOIDEA. 207 



1. Antedon balanoides, n. sp. (PL XXXIII. figs. 6, 7). 

 Specific formula — A.y- 



Description of an Individual. — Centro-dorsal a much elongated cone (5 '5 mm.), 

 bearing five converging double rows of cirrus-sockets, six or seven in each row. Its 

 lower portion has no functional sockets, but shows faint scars continuing the rows 

 downwards ; a deep interradial furrow between every two double rows. 



Thirty-five to forty cirrus-joints, of which the basal ones are short. The next till 

 the tenth or twelfth are much longer than wide, and develop a faint dorsal keel sloping 

 backwards from the distal edge, where it projects beyond the base of the next joint ; the 

 following joints are shorter and become compressed laterally. 



First radials concealed ; the second just in contact at their proximal angles, and 

 oblong, with a deeply incised distal edge, the centre being very short and raised to meet 

 the elevated blunt angle of the rhombic axillary. 



Ten arms ; the first brachials have long outer sides and a short raised centre ; the 

 second irregularly quadrate and similarly raised in the centre. Arm-joints triangular, 

 wider than long. Syzygies about the third, eighth, and twelfth brachials, and then at 

 intervals of two to six, usually three, joints. 



The second and third brachials have no pinnules ; the fourth bears a slender one of 

 fifteen joints and 7 mm. long. The next pair are generally stouter, and the following 

 ones less so, but of increasing length. 



Disk naked ; sacculi tolerably abundant on the pinnule-ambulacra. 



Colour in spirit, — the calyx a deep rose red ; the cirri and the ends of the arms white. 



Disk about 6 mm. ; spread probably about 1 2 cm. 



Locality.— Station 201, October 26, 1874; lat. 7° 3' N., long. 121° 48' E. ; 82 

 fathoms ; stones, gravel. A calyx and some arm-fragments. 



Remarks. — Only a single and much mutilated example of this remarkable type was 

 obtained by the Challenger. Its centro-dorsal is not unlike that of Atelecrinus in shape 

 (PI. VI. figs. 5, 7 ; PI. XXXIII. fig. 6), but the cirri are more numerous and the double 

 rows more regularly arranged than in that genus. These characters also distinguish the 

 type from Antedon defecta of the above list, which was dredged by the " Blake " in the 

 Caribbean Sea. 



The list given on p. 54 also includes six other ten-armed species of the " Blake " collec- 

 tion, viz. : — 



Antedon armata, Pourtales. 

 Antedon brevipinna, Pourtales. 

 Antedon columnaris, Carpenter. 



Antedon cubensis, Pourtales. 

 Antedon duplex, Carpenter, MS. 

 Antedon hageni, Pourtales. 



