18 Clark — A Revision of Thalassometridas and Himerometridae. 



Antedon duplex P. H. Carpenter 



" flava Koehler 



" incerta P. H. Carpenter 



" latipinna P. H. Carpenter 



" lusitanica P. H. Carpenter 



" magnicirra Bell 



" porrecta P. H. Carpenter 



" valida P. H. Carjaenter. 



Sub-family CHARITOMETRIN.E. 

 key to the included genera. 

 a* I Br and lower brachials with the dorso-lateral edge produced or everted, 

 forming a thin flange-like border. 

 b^ I Br with the proximal dorsal edges also produced ; genital pinnules 

 greatly and abruptly expanded; i Br and brachials rounded 

 dorsally, without ornamentation (IS) Pcecilometra. 



6* I Br with only the dorso-lateral edges produced ; genital pinnules very 

 regularly expanded, and evenly tapering; i Br and lower brachials 

 with the dorsal surface rugose or tubercular, and with a more or 

 less indicated rounded median line (19) Glyptomctra. 



a' I Br and lower brachials with no production of the dorso-lateral edge. 

 6^ third and fourth joint of the genital pinnules broad and nearly flat 

 on the outer side, but the fifth joint smaller. 

 c^ less than 12 cirrus joints; i Br and arm bases diverging at a wide 

 angle, so that the lower part of the animal is ))road and rounded 



(20) Sfrotomeira. 

 c^ more than In cirrus joints; i Brand arm bases diverging at a rela- 

 tively small angle, so that the lower part of the animal appears 

 conical (21) Charitometra. 



V^ genital pinnules evenly, and only slightly, expanded. 

 c^ lower and middle i)innules approximately the same in length. 

 d} cirri large and stout, with eighteen or more joints 



(22) Pachylometra. 

 d'- cirri weak and slender, with sixteen or less joints 



(23) Chlorometra. 

 c^ lower pinnules over twice as long as the middle pinnules 



(24) Crinometra. 



18. Poecilometra A. H. Clark. 

 The nominal species belonging to this genus are : 

 Pcecilometra accela (P. H. Carpenter) Poecilometra scnlaris (A. H. Clark). 



19. Qlyptometra gen. nov. 

 Genotype. — Antedon tuberosa P. H. Carpenter, 1888. 



Centro-dorsal thick discoidal, sometimes almost columnar, the cirrus 

 sockets in one, or one and a more or less conii)lete si'cond, crowded mar- 

 ginal rows; when in two rows, the tendency is toward a columnar, rather 

 than an alternating arrangement. 



