Efliiiiodermu II: Criiioidea. 315 



b • Cirri incroasing iii latoral diamotor voiy gradually, the distal 

 portion being not grcatly difforent from tho proximal; shortest 

 outcr cirrus sogmont.s measuring along tlunr dorsal protile one 

 third to one half moro tlian their lateral diametor. 



c ' P, with more than 25 segments A. hißda. 



c2 P, with loss than 20 segments A. hupferi. 



b^ Outer cirrus segments strongiy compressed laterallj, so that the 

 cirri are in lateral view nearly or quite twice as broad distally 

 as proximallj; longer proximal segments half again to twice as 

 long as the median diameter; shorter distal segments as long 

 dorsally as broad proximally. 



c' Size large ; cii-ri usually more than XL; interradial peii- 

 omic plates usually inconspicuous or undeveloped. 



A. petasus. 

 c'^ Size small; arms less than (iO mm in length; cirri less 

 than XXXV. 



d' Centrodorsal very low, evenly convex, Avith very 

 sloping sides; dorsal pole very small, from one 

 third to one half of the diameter of the centrodorsal; 

 arms 30 mm to 40 mm long. A. dühenii. 



d- Centrodorsal thin discoidal, the large flat dorsal pole 

 occupying more than two thirds the basal diameter; 

 arms usually about 60 mm long. A. moroccana. 



The species of the genus Antedon have the following geogi-aphical 

 ranges : 



Group A. 

 Group Characters. — Long, approximately uniform, ch-ri composed of 

 18 — 30 segments of whieh the distal are little if any shorter than the 

 proximal ; long and slender arms, composed of long segments. 



Group Range. — Northern and eastern part of the Mediterranean Sea: 

 from Malaga northeastward along the coasts of Spain and France to Italy, 

 thence southward to Sicily; Adriatic and Aegean Seas. 



1. Antedon niediterranea (Lamarck). 



Range. — From Malaga northeastward along the coasts of Spain and 

 France to Italy, thence southward to Sicily; Aegean Sea. 



3. Antedon adriatira A. H. Clark. 



Range. — Adriatic Sea (Trieste). 



; • ;^ ;? A R V 



