Lateral furrow: Groove between superomarginals 

 and inferomarginals. 



Madreporite: Stony sieve-plate at terminus of 

 water vascular system, on aboral surface, be- 

 tween margin and center of disc. 



Mamm/'ll/'for/n : Nipple-shajjed. 



Mai'ginah: One or two series of plates bordering 

 arms and disc, around periphery. 



Mouth frame: Ossicles surrounding mouth open- 

 ing. 



Oral: Surface on which mouth is located. 



Ossicle : Plate, or skeletal element. 



Papill/'fonn pedicellaria: Raised or elevated pedi- 

 cellaria. 



Papilla: Thin respiratory evagination of the body 

 wall which emerges between ossicles. 



Papular pore: Pore through which papula pro- 

 jects. 



Paxilla: Aboral plate drawn up into a column 

 which is usually crowned with spinules. 



PaxUlatr : Surface covered with paxillae. 



Paxilliform : Shaped like a paxilla. 



Pedicellarin: Small calcareous "pincher," of which 

 there are various types, used mostly to remove 

 particulate matter from surface of starfish. 



Pentagonal: Five-sided, without distinction be- 

 tween disc and arms. 



Podia : Tube feet. 



Radial furrow: Furrow on actinal surface running 

 from ambulacral groove to margin. 



Radius: Long radius (E), distance from center 

 of disc to tip of arm ; short radius (r), radius 

 of disc. 



Reticulate: Netlike, a network. 



Sessile pedicellaria: Pedicellaria resting directly 

 on surface, not raised or sunken. 



Spins : Sharp, calcareous projection resting on un- 

 derlying plate. 



Spinule: Very fine small spine. 



Stellate : Radiating, starlike. 



Sucker: Disc or flattened tip at end of tube foot. 



Superoviarginal : Plate of upper series of mar- 

 ginals. 



Sutural groove: Groove between adjacent mar- 

 ginals. 



Terete : Cylindrical, tapering. 



Tessellate : Mosaic of small fairly regular plates. 



Tridentate : With three teeth or valves. 



Triserlate : In a series of three. 



Tubercle: Calcareous projection shorter and 



thicker than spines. 

 Valvular pedicellaria: Pedicellaria with two 



valvelike pieces. 

 Wart: Calcareous projection larger than granule 



but smaller than tubercle. 



KEY TO THE ORDERS OF NORTH CAROLINA 

 ASTEROIDEA 



1 . Podia without suckers 



Podia with suckers 



2. Superomarginals absent 



S uj^eromargi nals present — 



3. Marginals conspicuous 



Marginals inconspicuous or 



4. Pedicellaria© absent 



Pedicellariae present 



2 

 3 



Platyasterida (I) 

 _ Paxillosida (II) 

 .. V'alvat.ida(III) 



absent 4 



Spinulosida (IV) 

 Forcipulatida (V) 



I. Key to the Species of Platyasterida 



1. Arms with wide transverse bands or 



blotches of black or brown. _ Luidia altemata 

 Arms without transverse color bands 2 



2. Inferomarginals with three spines, upper 



one much larger than others (yoimg 

 specimens may have only 



two) Luidia elegans 



Inferomarginals with two spines 3 



3. Paxillae quadrangular, skeleton com- 



pact Luidia clathrata 



Paxillae stellate, skeleton 



fragile Luidia- bernasconiae 



U. Key to the Species of Paxillosida 



1. Supei"omarginals separated 



by gap Ctenodiseus crispatus 



Superomarginals broadly in contact 2 



2. Marginal fi-inge of flattened, rectangular 



spines, usually not projecting much 

 Ijeyond margin ; large size. Tethyaster vestitus 

 Marginal fringe of acute spines form- 

 ing conspicuous border ; moderate size_ 3 



3. Rays long, slender: superomarginals 



small, numerous 4 



Rays not veiy long, robust; supero- 

 marginals large, few 5 



SEA-STARS OF NORTH CAROLINA 



135 



