CLARK: BOURGUETICRINIDAE 391 



be very slightly, almost imperceptibly, concave in the proximal half, 

 becoming slightly convex in the distal; though the proximal end of the 

 radial funnel is circular in outline, each radial distally gradually be- 

 comes convex dorsally so that in a dorsal view the distal end appears 

 in outline as a hexagon, with rounded angles; the distance from the 

 summit of the column to the distal edge of the radial circlet is 2 mm. 



The IBr x are very long, about twice as long as the proximal width, 

 with straight, slightly and regularly diverging sides. 



The IBr 2 (axillaries) are little more than half as long as the IBri, 

 considerably broader than long, with a blunt distal angle. 



Both the ossicles of the IBr series have a low obscure broadly rounded 

 median convexity, carrying forward the convexity of the distal portion 

 of the radials, and sharp straight sides; the IBr 2 has a shallow pit just 

 within the blunt distal angle. 



The twelve arms are slender and narrow, with a smooth dorsal pro- 

 file, the distal borders of the brachials not being produced, and meas- 

 ure 28 mm. in length from the distal edge of the radials; the brachials 

 are all united in pairs by non-muscular articulations ; the first brachial 

 is slightly trapezoidal, longer outwardly than inwardly, broader basally 

 than distally, half again as long as broad distally; the second brachial 

 is not much more than half as large. 



The first pinnule occurs on from the tenth to the fourteenth brachial, 

 usually on the tenth. 



The portion of the column attached to the crown is 22 mm. in length 

 and consists of forty-three segments, of which the first fifteen are short 

 and discoidal and the six following broader than long; the last five or 

 six segments of the column as preserved are about four times as long 

 as broad with very slightly, almost imperceptibly, enlarged ends, and 

 a similarly almost imperceptible median raised girdle. 



Another specimen, with the arms 25 mm. long, differs in having the 

 five basals, which are of unequal size, separated from each other by 

 sutures. 



Locality.— Southwest of Iceland (61° 44' N. lat., 30° 29' W. long.). 



Depth. — 1135 fathoms. 



Bottom temperature. — 3?0C. 



Rhizocrinus M. Sars. 



Rhizocrinus M. Sars, Forhandl. Vidensk. Selsk., 1864, p. 127 (geno- 

 type Rh. lofotensis, sp. nov.). 



Geographical Range. — North Atlantic only; from northern Florida to 

 Iceland, Ireland, and Norway, reaching to about 68?5 N. lat. on the 

 Scandinavian coast. 



Bathymetrical Range. — From. 140 to 2340 meters (77 to 1300 fathoms). 



Thermal Range.— From 0?1C. to 8?4C. and 48?7 Fahr. 



Included Species. — Rhizocrinus lofotensis M. Sars, and Rhizocrinus 

 verrilii A. H. Clark. 



