398 Bl 1. 1. II IX 82, UNITED STATES NATIONAL MUSEUM 



OXYMETRA ERINACEA (Harlloob) 



Plate 41, Figures 189, 190; Plate 42, Figure 194 

 Ant,, Ion erinacea IIartlaub, Nachr. Ges. G5ttingen, May 1890, p. 177 (description; Cebu); Nova 

 Acta Acad. German., vol. 58, No. 1, 1891, p. 38 (in key), p. 52 (detailed description and com- 

 parisons; Cebu), p. 58 (in first section of species of the Palmata group with spiny lower pin- 

 nules), pi. 3, fig. 29. — IIamann, lironns Klassen und Ordnungen des Tier-Reichs, vol. 2, Abt. 3, 

 1907, p. 1581 (listed).— A. II. Clark, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 13 (type of 

 Oxymetra) ; Smithsonian Misc. Coll., vol. 60, No. 10, 1912, p. 2 (identity) ; Crinoids of the Indian 

 Ocean, 1912, p. 37 (identity.) 

 Himeromelra erinacea A. II. Clark, Smithsonian Misc. Coll., vol. 50, 1907, p. 350 (listed). 

 Oxymetra erinacea A. H. Clark, Smithsonian Misc. Coll., vol. 60, No. 10, 1912, p. 2 (identity), p. 21 

 (Cebu; detailed description of the type), p. 22 (comparison with finschii and tenuicirra) ; Crin- 

 oids of the Indian Ocean, 1912, p. 37 (identity); p. 132 (synonymy; Cebu); Unstalked crinoids 

 of the Siboga-Expcd., 1918, p. 99 (in key; range). — Gislen, Kungl. Fysiogr. Sallsk. Handl., 

 new ser., vol. 45, No. 11, 1934, p. 33. 



Diagnostic features. — The longest cirrus segments are but little longer than 

 broad, and the distal cirrus segments are twice as broad as long or even broader; the 

 pinnules of the first four pairs are enlarged, moderately elongated, much stiffened, 

 spinelike, and more or less erect; there are 36-51 (usually more than 40) arms 90-115 

 mm. long; and the cirri have 48-63 (usually 50-60) segments. 



Description. — The centrodorsal is large and hemispherical and is almost entirely 

 covered by cirrus sockets. The dorsal pole is very small, irregular in shape, and 

 slightly concave. 



The cirri are XXX-XXXV (about XXV according to Hartlaub), 50-60, about 

 40 mm. long. They are rather scattered, rather thin and slender, and are distally 

 somewhat compressed laterally. The longer proximal segments are about as long as 

 broad. After the middle of the cirri the segments gradually decrease in length so 

 that those in the outer portion of the cirri are twice as broad as long. The shorter 

 segments in the distal half of the cirri have the distal dorsal edge thickened and 

 everted and very finely spinous, this eversion gradually becoming more and more 

 triangular in end view, the spinosity concurrently becoming gradually restricted to 

 the lateral part of the eversion, and on the terminal segments becoming a single 

 smooth sharp spine. The opposing spine is well developed. 



The radials are partially visible in the interradial angles of the calyx. The IBr, 

 are laterally united. The IBr 2 (axillaries) are pentagonal. The postradial series 

 divide four times, but the IVBr series arise only on the outer side of the IIIBr axil- 

 laries. In other words, the arms are arranged in 3, 2, 2, 3 order so that the normal 

 number of arms is (3+2+2+3)X5=50. The division series are 2 and are rather 

 slender and elongated. They are somewhat compressed laterally with a strongly 

 convex dorsal surface and perfectly straight sides. Small synarthrial tubercles are 

 present. The division series are rather widely separated, and the outermost arms 

 are rather rarely in contact. The two ossicles following each axillary, with the 

 exception of the first brachials, are always only partially united. 



The 51 arms in the type specimen are rather slender and relatively short and are 

 105-115 mm. in length. Their dorsal surface is entirely smooth. The first brachials 

 are strongly rounded dorsally, somewhat thickened dorsoventrally, and as long as 

 broad. The second brachials are slightly longer exteriorly than interiorly. The 

 first syzygial pair (composed of brachials 3+4) is markedly longer than broad. 



