A MONOGRAPH OF THE EXISTING CRINOIDS 363 



The third segment is two and one-half times as long as broad, and those following 

 increase in length, the distal being four times as long as broad. The terminal segment 

 is about four times as long as the basal width, conical, ending in a sharp point or in a 

 small group of spines. The second and following segments have a faint keel on the 

 outer side. The distal border of the third segment is armed with minute spuies. On 

 the succeeding segments these increase in size so that the last eight or nine have the 

 distal border armed with long though exceedingly fine spines. P3 is 16 mm. long with 

 17 segments. It resembles P2 but is very sUghtly stouter, the first segment is not so 

 broad, the following segments are relatively longer, and the carination running along 

 the outer side is more prominent. P4 is 15 mm. long with 17 segments. It resembles 

 Ps but is shghtly more slender. Distally it is about as slender as P2, but it is somewhat 

 stouter basally, tapering more rapidly on the first six or seven segments. Pj is 13 

 mm. long with 16 segments, and is more slender than Ft, especially beyond the basal 

 third. The third-fifth segments support a gonad, and their ventrolateral borders are 

 slightly extended beneath it. The pinnules immediately following are similar, these 

 later passing into the sharply prismatic distal pinnules. On an arm arising from a 

 IBr axillary Pi is as described; Pj is 11 mm. long with 13 segments; P3 is 14 mm. long 

 with 13 segments; P4 resembles Pj on arms arising from a IIBr axillary and bears a 

 gonad. It is 12 mm. long with 15 segments. On arms arising from a IBr axillary 

 the enlarged oral pinnules are shorter and more slender than on arms arising from 

 a IIBr axillary. 



Locality. — Danish Expedition to the Kei Islands; Dr. Th. Mortensen; station 54; 

 85 meters; sand and coral; May 9, 1922 (1, C. M.). 



Remarks. — In the absence of triple dorsal processes on the outer cirrus segments, 

 the absence of ventral carination of the cirri, the elongate earlier cirrus segments, the 

 small number of arms, and the slender build, this species agrees with xV. diana. It 

 difi'ers, however, in having much shorter cirri with only half as many segments, in 

 lacking synarthrial tubercles, and in various other details. 



NEOMETBA ACANTHASTER (A. H. Clark) 



[See vol. 1, pt. 1, fig. 89 Gateral view), p. 147.) 



Calometra acanthaster A. H. Clark, Smithsonian Misc. Coll., vol. 52, part 2, 1908, p. 224 (description; 

 Albatross station 5153); Proc. U. S. Nat. Miis., vol. 39, 1911, p. 544 (specific relationships; cirri 

 compared with those of alecto). 



Neometra acanthaster A. H. Clark, Crinoids of the Indian Ocean, 1912, p. 184 (synonymy; locality); 

 Rec. Western Australian Mus., vol. I, pt. 3, 1914, p. 128 (specific relationships), p. 130 (char- 

 acters; range); Unstalked crinoids of the Siboga-E\ped., 1918, p. 132 (in key; range); Smith- 

 sonian Misc. Coll., vol. 72, No. 7, 1921, pi. 9, fig. 45.— Gisl£n, Kungl. Fysiog. Sallsk. Handl., 

 new ser., vol. 45, No. 11, 1934, p. 25. 



Diagnostic features. — This species seems to be easily distinguished from all the 

 others in the genus by the sharp carination of the midventral line of the cirri, com- 

 bined with the presence of 30 arms resulting from the occurrence of I II Br series on 

 the outer side of each ray. The cirri have about 35 segments and arc about one 

 third of the arm length. 



Characters. — This species comes nearest to N. multicolor from which it differs in 

 a number of features that appear to be perfectly constant. 



