84 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



Dorsal surface. Of the radial pentagon, the surface which is covered by the cen- 



trodorsal (see fig. 12, p. 65). 

 Dorsal tip. Of centrodorsal; that portion of the centrodorsal, surrounding the bare 



dorsal pole, which bears the so-called small mature cirri (see fig. 310, p. 269). 

 Dorsal transverse ridge. A transverse ridge found on the outer cirrus segments; 



this structure is only developed in a few species, where it takes the place of 



doisal spines (see figs. 349, 352, p. 291). 

 Dorsal tubercles. Tubercular processes developed on the dorsal side of the outer 



segments of the cirri ; they may be described as short and blunt dorsal spines ; 



as with the latter there is ordinarily only one to each cirrus segment, though 



sometimes two or even three are found side by side (see figs. 346, p. 289, and 



370, p. 299). 



Dorsocentral. The terminal stem plate of the stalked comatulid larva; the primi- 

 tive dorsal central plate; this term is sometimes used instead of centrodorsal 



(see figs. 2, p. 61, 532-540, pi. 3). 

 Dorsolateral processes. The produced dorsolateral borders of the ossicles of the 



division series and of the first two brachials, as seen in Pwcilometra. 

 Dorsoventral axis. See Axis 2. 



E. 



Embryonic 6asaZs. ^Basals which appear as true basals only in the young, in the 



adult becoming metamorphosed into a rosette. 



Among the comatulids true basals are found only in the Atelecrinidae, 



but embryonic basals occur in the species of all the other families. 

 Endocydic. With the mouth situated approximately in the center of the coil of the 



digestive tube, and therefore approximately in the center of the disk (see figs. 



20, 22-24, p. 69, and pp. 110, 111). 



This includes all of the comatulids except those belonging to the family 



Comasteridaa and Uintacrinida3. 

 Entire disk. A disk in which the free borders of the interambulacral areas are 



straight or slightly convex (see figs. 15-19, p. 67). 

 Entire regeneration. See Regeneration B 1. 

 Entrochi. A series of trochitae joined together as in life; a section of a stem or 



column. 



Epizygal. The distal segment of a syzygial pair. 

 Exocyclic. With the mouth situated on the border of or outside of the coil made by 



the digestive tube, and therefore marginal or submargmal on the disk (see 



figs. 21, 25-28, p. 69, and pp. 110, 111). 



This includes most of the species included in the family Comasteridse, 



and the species of the Uintacrinidae. 

 External arm. The external arms are the two lying on the outer sides in reference 



to the IBr series; more rarely the reference is to the IIBr series, but in this case 



the fact that the second division series is the determining series is always 



mentioned (see figs. 616, p. 87, and 78, p. 131). 



