CLARK: CRINOID FAMILY ANTEDONIDAE 129 



Argyrometra mortenseni, sp. nov. 



Diagnosis. — This species is easily distinguished from A. crispa by 

 the much more expanded distal ends of the cirrus segments (in crispa 

 the dorsal and ventral profiles of the cirrus segments are everywhere 

 practically parallel), and by the different relationships of the earlier 

 pinnules. 



Pi is 3.3 mm. long, slender and evenly tapering, composed of 12 seg- 

 ments of which the first is slightly broader than long, the second and 

 third are very slightly longer than broad, and the following become 

 progressively elongated, being between four and five times as long as 

 broad distally; the segments are cylindrical and smooth, with little or 

 no development of spines on the distal edges. P 2 is 4 mm. long, very 

 slightly stouter, composed of 12 segments of which the distal are more 

 elongated than those of Pi. P 3 is 5 mm. long with about 12 segments, 

 about as stout basally as P2 but tapering more slowly and hence appear- 

 ing stouter, with relatively shorter segments which beyond the third 

 have prominently overlapping and finely spinous distal ends. The 

 following pinnules resemble P 3 . 



The cirri have 17 segments of which the longest are from four to 

 six times as long as the terminal diameter. The arms are about 30 

 mm. long. 



Locality. — North Cape, New Zealand. 



Depth. — Sixty fathoms. 



Sarametra, gen. nov. 



Genotype. — Zenometra triserialis A. H. Clark, 1908. 



Diagnosis. — The division series and arm bases are very spiny; the 

 very long rounded conical centrodorsal bears three regular columns of 

 cirrus sockets in each radial area, the radial areas being delimited by 

 broad bare lines; the cirri have 50-60 segments of which the proximal 

 are more or less elongated and the distal are short, never longer than 

 broad, and bear prominent dorsal spines; all of the pinnules are present; 

 the size is large, the arms being about 150 mm. long. 



Geographical Range. — Known only from the Hawaiian Islands. 



Bathymetrical Range. — Between 346 and 633 meters. 



Included Species. — Sarametra triserialis (A. H. Clark). 



Orthometra, gen. nov. 



Genotype. — Trichometra hibernica A. H. Clark, 1913. 



Diagnosis. — The cirrus segments, which are 25-33 (usually nearer 

 the latter) in number, are cylindrical, without expanded distal ends, 

 and short, the longest (third-fifth) being about one-third again as long- 

 as broad, and the distal slightly broader than long; the elements of the 

 IBr series and the lower brachials are without lateral processes, and 

 are widely free laterally. 



