A MONOGRAPH OF THE EXISTING CRINOIDS 349 



tea). HARTLAUB, Bull. Mus. Comp. Zool., vol. 27, No. 4, 1895, p. 131 (systematic and bathy- 

 metrical relationships.) BATHER, in Lankester, A treatise on zoology, pt. 3, Echinoderma, 1900, 

 fig. ix, 2, p. 102. HUTTON, Index faunae Novae Zealandiae, 1904, p. 290 (listed). MINCKERT, 

 Arch. Naturg., Jahrg. 71, 1905, vol. 1, p. 169 (syzygies). HAMANN, Bronn's Klassen und Ord- 

 nungen des Tier-Reichs, vol. 2, Abt. 3, 1907, p. 1578 (listed). A. H. CLARK, Crinoids of the 

 Indian Ocean, 1912, p. 33 (identify). 



Charitometra basicurva A. H. CLARK, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 361 (listed); 

 Geogr. Journ. vol. 32, No. 6, 1908, p. 603 (type of non-oceanic group) ; Proc. Biol. Soc. Wash- 

 ington, vol. 22, 1909, p. 20 (listed); Crinoids of the Indian Ocean, 1912, p. 33 (identity), p. 226 

 (synonymy; locality); Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 49 (published references 

 to specimens in the B. M.; Challenger station 170A); Unstalked crinoids of the Szfcoja-Exped., 

 1918, p. 191 (in key; range). GISL^N, Ark. Zool., vol. 19, No. 32, Feb. 20, 1928, p. 9 (notes). 



Diagnostic features. The brachials from the fourth onward have prominently 

 thickened and everted, and beaded or tuberculated, distal edges, this feature grad- 

 ually dying away after the brachials become triangular; the 10 arms are about 100 

 mm. long. 



Description. The centrodorsal is hemispherical with a very rough dorsal pole 

 and small interradial processes. According to the figures given by Carpenter the 

 cirrus sockets are evenly distributed, in 10 irregular columns in the young and 15 in 

 the fully grown. 



The cirri are about XX, 18-20; the segments are very stout, most of them longer 

 than broad. The distal ends of the earlier segments overlap slightly, those of the later 

 ones more strongly, especially on the dorsal side so as to produce a blunt spine on the 

 distal edge, which is rather sharp on the penultimate. 



The radials and sometimes portions of the IBri are concealed. The IBrj are 

 short and bandlike, in close lateral contact; they have raised edges which are often 

 somewhat crenulate, and there is usually a slight tubercle on the distal border cor- 

 responding to one on the axillary. The IBr 2 (axillaries) are short and pentagonal 

 with a wide, open angle and more or less crenulated edges. The dorsal surface is very 

 convex with the margin more or less flattened, and with sharply flattened wall-like 

 sides. 



The 10 arms are about 100 mm. long and are composed of about 120 brachials. 

 The first brachials are short, nearly oblong, and are closely united interiorly. The 

 second brachials are more wedge-shaped. Both rise toward their apposed edges to 

 form a median elevation (synarthrial tubercle) like that between the elements of the 

 IBr series. The following brachials are short until about the twelfth, after which 

 they are longer and more triangular, gradually becoming wedge-shaped. The ter- 

 minal brachials are elongated and slightly compressed laterally. The first four bra- 

 chials are wall-sided with flattened margins like the axillaries. In the proximal portion 

 of the arms the distal edge of each bracbial stands up as a sharp crenulated ridge from 

 which the surface slopes backward. Farther out on the arms as the brachials become 

 longer this sudden rise disappears, and the brachials overlap in the ordinary way. 



Syzygies occur between brachials 3+4 and again from between brachials 10+11 

 to between brachials 17 + 18; the distal intersyzygial. interval is from 2 to 17 (usually 

 4 to 8) muscular articulations. 



PI is short with about 22 segments of which the 6 pr ^ximal are trihedral and much 

 flattened on the outer side with a marked dorsal keel v hich is lost in the smaller ter- 



