174 BUULETIN '76, UNITED STATES NATIONAL MUSEUM. 



a'. Abactinal plates entirely covered by large flat circular, quadrate, oval, elliptical, triangular, and 

 polygonal granules, whose edges are more or lees free; secondary abactinal plates not forming 

 connecting pieces between primary plates; gome of the adambulacral plates with furrow series 



replaced by a largo bivalved pedicellaria CTyptopeltastcr Fisher, p. 237. 



a". Abactinal plates not entirely covered by large flat granules whose edges are more or less free; 

 secondary plates forming connecting pieces between the primary plates; no large bivalved 

 pedicellariie on furrow margins. 

 6'. Granules of body sheathed in a thick pulpy membrane and furrow spines three to six in number 



with remarkably thin, compressed, expanded tips Evoplosoma Fisher. 



b^. Granules not sheathed and hidden by a thick pulpy membrane; granules typically forming a 

 single series around the plate; furrow spines one to three in number, not flaring or chisel- 

 like at tip nippasleria Gray, p. 223. 



IV. Abactinal skeleton stellate reticulate, overlaid by a thick skin obscuring the outlines of the plates; 

 marginal plates heavy, beset with large granules, the inferomarginals with large bivalved pedicel- 

 larise also; actinal plates with coarse granules and large pedicellarise; adambulacral armature, 

 a few (about five) relatively short, slender, furrow spines, and one or more short heavy actinals; 



all pedicellariie bivalved Antheneinx. 



a'. Abactinal membrane beset with bivalved pedicellariae and scattered granules; superomarginals, 

 also, with large pedicellariae; abactinal plates stellate, the secondary plates connecting the lobes 



to form a regular reticulated skeleton Anthenca Gray. 



a'. Abactinal surface without pedicellariae, with a few hemispherical tubercles along radial line, 

 and large hemifi^herical granules near marginal plates; abactinal plates relatively small, irreg- 

 ular, reticulate; two actinal adambulacral spines; actinal plates very distinct. 



Pseudoreaster Verrill. 



NOTE ON PEDICELLARI.E. 



Several sorts of pedicellarise have been mentioned in the foregoing key. To 

 avoid confusion, these will be explained briefly. All the pedicellarite occurring in 

 the Phanerozonia are of the sessile type — that is, the jaws are not attached to a 

 special basal piece, but spring directly from the plate or from a specialized depression 

 or foramen in the plate. 



A. Incipient and pseudo-pedicellariiie. The jaws do not spring from a specialized depression or 



foramen. 



1. The epineleta stand on separate plates and meet over the suture between the plates. 



lo. Spinelets form .simple fascioles; fasciolar. 



16. Spinelets are more specialized and in definite areas, or are more definitely coordi- 

 nated into a special apparatus, as two opposed combs; pectinate. 

 \c. The spinelets of a series fuse or widen, and thus form valves; valvular. 



2. The spinelets stand usually on one plate, forming a more or less conical group; not found 



in the Goniastcridae; fascicular or fasciculate. 



B. Alveolar or tong-shaped pedicellariae. The jaws spring from a specialized pit or foramen, and 



vary in size and proportions. 



1. The jaws have no specialized depressions into which they fit when opened; the jaws 



are higher than wide and often spatulate; foraminate, also spoken of as two-jaioed 

 spatulate, or as spatulate. 



2. The jaws are low and wide, with no specialized depression into which they fit when 



opened. The pedicellariae are mereslita, orresemble a miniature bivalved shell. This 

 form intergrades with the smiple foraminate type of various shapes. It is found in a 

 typical form in Eippasteria, Cryptopellaster, Gilbertaster, Anthenea, and other genera; 

 bivalved. ' 



3. The jaws when opened fit into a specialized depression. This type is best developed in 



the Linckiidse, but occurs in Calliasler, Astroctramus, Lydiasler; excavate or sugar-tongs. 



