314 A. H. Clark. 



characteristic east Atlantic genus, is restricted to the region east of the 

 central part of the Bay of Bengal, and that the fossil comatulids of Europe 

 in so far as they have been aceurately determined also belong to genera 

 similarly restricted, appears to otfer indubitable proof that the path b} 

 which these genera reached the Atlantic or the past seas covering more 

 or less of Europe was „overland" from the Bay of Bengal to the north- 

 ward of what is now India, or at least southern India; that is, that the 

 Mediterranean Sea at the time these crinoids attained approximately their 

 present ränge was connected with the Bay of Bengal, across Asia. Had 

 these genera ever passed through the Arabian Sea or through the Red 

 Sea we would surely find some representative of theirs there now. 



The Status of the species of the genus Äntedon as at present under- 

 stood, the charaetors diflerentiating the seven species, and the distribution 

 of each, is briefly set forth in the following key and accorupanying list of 

 species showing their respective ranges. 



Key to the species of the Genus Antedon. 



18 or more cirrus segments, all of which ar long, the distal dift'ering 

 but slightly from the proximal; distal portion of cirri not compressed 

 laterally, so that the cirri appear of the same diameter throughout ; 

 no perisomic interradials in angies of calyx; arms slender and very 

 long, the proximal triangulär brachials beiug considerably longer than 

 broad; IBrj long, not more than three times as broad as long, regu- 

 larly oblong or slightly trapozoidal, the lateral edges making usuallv 

 a straight line, more rarely a broadly obtuse angle, with those of the 

 IBra (axillary). 



b ' Cirrus segments usually 18 — 20 A. ynediterranea. 



b - Cirrus segments usually 24 — 28 A. adriatica. 



17 or fewer cu'rus segments (more than 15 only in exceptional casesj 

 of which the proximal are long but the distal, which are more or 

 less compressed laterally, are shorter, usually about as long dorsallv 

 as broad, and broader, usually twice as broad, in lateral view; inter- 

 primibrachial plates usually prominently developed in tlie angies of 

 the calyx; arms comparatively short and stout, the proximal triangulär 

 brachials being usually noticeably broader than long, never longer 

 than broad; IBr, short, rarely so few as three times as long as broad, 

 much narrower distally than proximally so that the lateral angies of 

 the axillaries project beyond the distal angies of the IBr,. 



