PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 43 



moderate to strong dorsal projections on the short distal segments; P, very long and 

 flagellate, ^vith 30 to 82 short segments, the distal ones very rarely longer than broad 

 and often with dorsal convexities simulatmg the combs of the comasterids; P2 usually 

 similar but sometimes with slightly longer segments. 



Thysanometrinae (see fig. 14) : Centrodorsal low hemispherical, rarely almost 

 discoidal or subcorneal, with the cirrus sockets irregidarly arranged; cirri slender, often 

 with the 15 to 30 segments very elongate, dorsal spines completely absent; P, long and 

 flagellate, ^vith 30 to 40 short segments, of which even the distalmost are rarely longer 

 than broad; P2 similar in length to Pi but with only half as many segments, which are 

 therefore much longer. 



Antedoninae (see figs. 3-13): Centrodorsal discoidal to hemispherical to rounded 

 conical, with tlie cirrus sockets crowded irregularly; cirri relatively short, with segments 

 rarely numbering more than 20, and completely lacking dorsal processes; Pj with all the 

 segments, except the basal ones, nearly always longer than broad, often several times 

 longer, usually 12 to 20 segments, but sometimes (as in Antedon and Annametra) they 

 may number up to 50 and may be rather short; P2 longer than Pj in about half the 

 genera, though usuallj' with a similar number of segments; in the rest it is shorter, with 

 fewer segments. 



Perometrinae (see figs. 19-24): Centrodorsal low to high rounded conical, with 

 the cirrus sockets crowded irregularly; cirri rather long with 25 to 55 segments, the distal 

 ones with conspicuous dorsal prominences; Pi with about 12, rarely up to 20 moderately 

 long segments; P2 similar but smaller; P^ sometimes and P, occasionally absent. 



Bathymetrinae (see figs. 37-47): Centrodorsal conical to hemispherical, rarely 

 almost discoidal, with the cutus sockets crowded and usually alternating or UTegular in 

 position; cirri usually with 15 to 35, rarely over 45, segments, of which the longest are 

 always longer than broad and may be up to six times as long; the distal segments 

 usually have dorsal prominences; Pi usually with about 20 elongate segments, rarely 

 up to 42 ; P2 may be shorter or longer, it is often the first genital pinnule. 



IsoMETRiNAE (see figs. 35-36) : Centrodorsal conical to hemispherical, with the 

 cirrus sockets alternating or irregularly placed; cirri stout, usually with 30 to 40 short 

 segments, rarely up to 75, the longest segments never much longer than broad, the distal 

 ones \vith dorsal keels, P, fairly stout with 5 to 17 moderately elongated segments; 

 P2 either longer or shorter than Pi with 6 to 14 segments; genital pinnules marked off 

 from those of all the other subfamilies by the conspicuous lateral expansion of two or 

 more of the segments bearing the gonads. 



Subfamily Antedoninae 



[Note by A.M.C] The word 'Antedoninae' was used by Delage and Herouard in 

 their Traite de Zoologie Concret (vol. 3, 1903, p. 394), for the family Antedonidae in 

 Bather's sense. This, and their other family names, formed by adding the suffix 

 '-inae' to the name of the type genus, were not generally adopted and the first author of 

 Antedoninae as a subfamily was A. H. Clark. 



Antedoninae A. H. Clark, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 176 (includes Antedon, 

 Masligometra, Compsomelra and Iridometra) ; in Michaelsen and Hartmeyer, Die Faun.i Siidwest- 

 Australiens, vol. 3, Lief. 13, Crinoidea, 1911, p. 438 (1 genus and 2 species in Australia); Mem. 

 Australian Mus., vol. 4, 1911, p. 725 (genera Masligometra and Iridometra absent from Australia) ; 



