130 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxm. 



aa. Less than 25 cirrus joints, usually smooth. 



h. Centro-dorsal conical, the cirri in 5 radial clusters; cirri rather slender, with 

 16 smooth joints; basals and first radials large and prominent. 



(15) A. qarrettiana. 

 hb. Centro-dorsal discoidal, the marginal cirri without definite arrangement; 

 basals and first radials concealed; radials narrow, rounded or flattened; 

 cirri stout and rounded basally, slender and compressed distally. 



(16) A. or ion. 



E. Ten-armed species with no pinnule on the third brachial. 



a. First pinnule the longest (21 ) ^1. ruber. 



aa. First two pinnules about equal, or the first slightly shorter than the second; 

 long conical processes at the junctions of the two outer radials and first two 

 brachials (22) A. dwmedeir. 



aaa. Second pinnule much elongated, the joints with serrate ends; radials and 

 lower brachials smooth, not tubercular (23) A. tlgrhia. 



F. Ten-armed species with the first pinnule the longest. 



a. About 30 smooth cirrus joints, the basal ones elongate (24) ^1. bowersi. 



G. Bidistichate species with an unplated disk and no definite ambulacral skeleton; 



the sides of the lower brachials are scarcely, if at all, flattened; the first pinnule 



smaller than its successors [Palm ata group] . 



a. The third brachial has a pinnule. 



b. One post-radial axillary; the rays (juite free laterally. 



c. 40-45 cirrus joints; lateral flange-like processes on the radials and distichals. 



(25) A. abbotti. 

 bb. One post-radial axillary, the radials and distichals in close contact laterally. 



(26) A. stylifer. 

 bbb. Two or more post-radial axillaries. 



c. Third pinnule larger than the second. 

 d. Cirri not sjiiny. 



e. Cirri elongate, with 40 or more joints (27) A. delicatissivia. 



H. A syzygy in the radial axillary [Elegans group]. 



a. Cirri very stout, the joints about as broad as long; there are no dorsal spines, 

 but the penultimate joint bears a strong opposing spine; second radials visi- 

 ble (11 arms in the type) (28) A. rubroflava. 



I. ANTEDON MULTICOLOR, new species. 



Centro-dorsal a thick di.sk, bearing 15 cirri in a single marginal row; 

 these are 20 mm. long with about 35 short joints, of which the sixth 

 and seventh are squarish, the others wider than long; the joints over- 

 lap somewhat and distally bear small dorsal spines. 



First radials completely anch^doscd laterally, extending up in a 

 tongue-like process in each interradial area to the disk, thus widely 

 separating the second radials; second radials oblong, slightly over 

 twice as wide as high; axillaries pentagonal, slightl}- less than twice 

 as wide as high. Axillaries and second radials of each ray rounded 

 and widely separated from those of adjacent rays; the lower part 

 of the calyx bears a strong resemblance to that of Atelecriniis 

 IjalanoldeH. ; but the "basal ring" in the case of Antedon mvlticolor 

 is formed of the coalesced first radials, consequently there are only 

 two radials above it, whereas in Atelecrinus there are three. The 

 articulation between the two outer radials in Antedon midticolor is 



