22 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



History. The genus Basilometra was originally described by me in February 

 1936 to include the single species B. boschmai. On August 11, 1936, Dr. Torsten 

 Gislen again described the same type under the new generic name Rhadinometra, with 

 the single species R. dawydovi. 



BASILOMETRA BOSCHMAI A. H. Clark 



PLATE 5, FIGURES 16-19 



Basilometra boschmai A. H. CLARK, Temminckia, vol. 1, 1936, p. 295 (listed), p. 305 (description; 



Ternate, 2-4 meters), pi. 7, figs. 1-4. 

 Rhadinometra dawydovi GISL^IN, Kungl. Fysiogr. Sallsk. Lund Forh., vol. 7, No. 1, Aug. 11, 1936, 



p. 5 (French Indo-China), p. 6 (range), p. 15 (Pulo Condor, Cochin China; Re'am, Cambodja; 



description and discussion), figs. 5, 6, p. 15, fig. 7, p. 18. 



Description. The centrodorsal is thick discoidal with the slightly concave dorsal 

 pole about 4 mm. in diameter. The cirrus sockets are arranged in three closely 

 crowded irregular marginal rows. 



The cirri are XXVI, 47-49, moderately stout and uniform, 35 mm. in length. 

 The first segment is short ; those following increase very slowly in length to the eighth- 

 twelfth, which are about one-third again as broad as long, and those succeeding de- 

 crease very slowly and gradually so that those in the terminal fourth of the cirri are 

 about twice as broad as long. The longer proximal segments are very slightly con- 

 stricted centrally. The eighth and following segments have the distal dorsal edge 

 thickened and provided with an even row of 4-6 rounded tubercles. This row of 

 tubercles gradually becomes bowed proximally and at about the beginning of the ter- 

 minal quarter of the cirri becomes V-shaped with the tubercles on either side of the 

 apex of the V more or less broadened and fused. After three or four segments this V 

 resolves itself into a pair of small tubercles situated close together side by side, one on 

 either side of the median line. On the last 4-7 segments before the penultimate there 

 is a single small median tubercle. In lateral view the cirri are practically of uniform 

 width throughout. The dorsal processes are so low that at first sight the cirri appear 

 smooth. The opposing spine is triangular, blunt, arising from the entire dorsal 

 surface of the penultimate segment. It is small and inconspicuous, though larger 

 than the processes on the preceding segments. The terminal claw is slightly longer 

 than the penultimate segment, and is stout and moderately curved, usually rather 

 more strongly proximally than distally. 



The radials are visible as narrow curved bands beyond the rim of the centro- 

 dorsal. The IBri are 5-6 times as broad as long in the median line, half again as long 

 laterally as in the median line, with the distal border strongly concave and the lateral 

 edges strongly convergent and slightly concave. The IBr 2 (axillaries) are broadly 

 pentagonal, and are from half again to nearly twice as broad as long. Their lateral 

 borders are about as long as those of the IBri, with which they make a very broadly 

 obtuse angle. The lower ventrolateral angle is abruptly produced laterally in the 

 form of a narrow high tubercle, over a similar abrupt lateral production of the anterior 

 ventrolateral angle of the IBr^ A small and abrupt synarthrial tubercle may be 

 present on the articulation between the IBri and IBr 2 . Of the 10 IIBr series present 

 8 are 4(3 + 4) and 2 are 2. Of the 20 IIIBr series 18 are 2 and 2 are 4(3+4). The 

 IVBr series are 4(3 + 4) except for a single one which is 2. Further division series, 



