276 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



given. In 1934 Prof. Torsten Gisl6n listed Perissometra invenusta among the comatu- 

 lids with the Heteromelra bengalensis type of arm division. 



GLYPTOMETUA LATERALIS (A. H. Clark) 



Plate 29, Figure 87 



[See also vol. 1, pt. 1, fig. 370, p. 299; pt. 2, figs. 240, p. 197, 303, p. 223, 676, 677, p. 338, 868-873, 



p. 425, pi. 54, fig. 1347.] 



Charitometra lateralis A. H. Clark, Proc. U. S. Nat. Mus., vol. 34, 1908, p. 214 (in ke3'), P- 226 (de- 

 scription; Albatross station 4179; also stations 4177, 4180). 



Glyplometra lateralis A. H. Clark, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 19 (listed); vol. 25, 

 1912, p. 81 (comparison with G. [Perissometra] timorensis); Crinoids of the Indian Ocean, 1912, 

 p. 224 (synonymy; locality); Bernice P. Bishop Mus. Bull. 195, 1949, p. 75 (Albatross stations 

 4177, 4179, 4180), p. 116 (station data). 



Calyplometra lateralis A. H. Clark, Journ. Washington Acad. Sci., vol. 6, No. 17, 1916, p. 608 (listed); 

 Unstalked crinoids of the Siboga-Exped., 1918, p. 189 (references). 



Diagnostic features. — The cirri, which are arranged in 15 columns on the centro- 

 dorsal, are 30-40 mm. long with 15-21 segments of which the distal are markedly longer 

 than broad; the 10 (rarely 11) arms are 160-180 mm. long and the division series and 

 lower brachials aro coarsely rugose with the lateral edges everted, each of the proximal 

 brachials with a low broad hump. 



Description. — The centrodorsal is very thick discoidal, or almost columnar, more 

 rarely truncated conical. The closely crowded marginal cirrus sockets are arranged 

 roughly in 2 rows and 15 columns. 



The cirri are XXX, 15-21 (usually 16-19), from 30 mm. to 40 mm. in length. The 

 first segment is about half as long as broad, the second is almost as long as broad, the 

 third is rather longer than broad, and the remainder are about half again as long as 

 broad. The last 4 or 5 segments have the median portion of the distal dorsal edge 

 rather prominent, and the penultimate bears a small opposing spine which is usually a 

 blunted tubercle, but sometimes sharp and directed obliquely distally. The terminal 

 claw is not so long as the penultimate segment, and is moderately slender and moderately 

 curved. 



The ambulacra of the arms and pinnules are extensively plated. 



The ends of the basal rays are visible as rounded tubercles in the interradial angles 

 of the calyx. 



The radials, and usually also all the IBri, are concealed by the centrodorsal. The 

 IBr 2 (axillaries) are low and broad, about three times as broad as long, with the distal 

 angle broad and usually more or less blunt or rounded. IIBr series, when present, are 2. 



The 10 or 1 1 arms are 160 to 180 mm. in length. The first two brachials are oblong, 

 very short, three or four times as broad as long. The first syzygial pair (composed of 

 brachials 3+4) is about twice as broad as long. The following eight or nine brachials 

 are wedge-shaped, about twice as broad as long, those succeeding becoming triangular, 

 and after the eighteenth as long as broad, the terminal brachials becoming wedge- 

 shaped again and elongate. The IBr, and the first three brachials have the proximal 

 and distal edges everted and crenulate, often extravagantly so, dovetailing with the 

 edges of the adjacent segments. The lateral edges of these ossicles are strongly everted 

 and thin, those on adjacent arms being closely appressed and together standing out as 

 narrow interradial keels which are equal in height to the proximal and distal eversion 



