BARBADOS-ANTIGUA REPORTS 19 



composed of numerous short segments; 20-30 arms; 

 proximal portion of animal usually highly ornamented 

 with spines or tubercles, though sometimes plain 



CrUwmetra 



82 cirri long, with more than 30 segments of which the out- 

 er bear prominent dorsal spines; eentrodorsal rather 

 small, more or less conical, the cirrus sockets arranged 

 in ten columns; first pinnule longer and stouter than the 

 following 



fi the segments in the basal half of the genital pin- 

 nules are much broadened, forming a roof over the 

 gonads; 10 arms 



Horaeometra 



f- the segments of the genital pinnules are not ex- 

 panded; usually between 20 and 30 arms 

 gi very spinous; the edges of the elements of the 

 division series and lower brachials are armed 

 with long spines, and each of the middle and 

 outer brachials bears a single long curved later- 

 ally compressed spine which overlaps the base of 

 the brachial succeeding; division series and arm 

 bases narrow, strong convex dorsally and more 

 or less separated 



Stylometra 



g- smooth; the edges of the elements of the divi- 

 sion series and brachials are unmodified; divi- 

 sion series and arm bases broad and in close 

 lateral apposition 



Crotalometra 

 a2 A stem is present 



bi the short thick stem or stalk consists of a single unjointed element 

 by which the animal is solidly attached to corals or other hard ob- 

 jects; the arms are very short and stout, six of them being consid- 

 erably larger than the other four 



Holopus 



b2 the stem is long and many jointed; its distal end is never attached 

 bearing five articulated processes or cirri; the stem ends ab- 

 ruptly, exposing the distal face of one of the columnals, which 

 is usually more or less worn ; size large 

 di all of the division series are of two elements 



Endoxocrinus 



d- the first division series is of two elements, the following 

 always of more than two, the number increasing distally 



Isocrmus 



