282 VERRILL 



Pedicellariae are sometimes lacking, but usually present and some- 

 times large. They may be bivalvular, sessile and seated over a pore 

 (foraminate), or implanted in special pits on the plates (fossate) ; or 

 else papilliform or fasciculate, composed of two to four or more 

 modified, convergent spinules ; or pectinate, consisting of two comb- 

 like groups of spinules convergent over a suture between two 

 adjacent plates, as in Luidiasler (see pi. xxxiv). 



The sessile valvular pedicellariae with a pore between the valves 

 are called foraminate; they may have two, or more than two, valves 

 {bivalvular and trivalvular, etc.). In the suborder Valvulosa they 

 are often provided with a pair of pits or fossae, into which the valves 

 fit when widely open. The valves in these are often spatulate, spoon- 

 shaped, tongs-shaped, or battledore-shaped, and usually may best 

 be called platalciform or spatulate. When furnished with receiving 

 pits, they have been called excavate; but fossate seems to be a more 

 appropriate term. 



The peculiar papilliform pedicellariae of the Paxillosa, with two to 

 four or more slender valves, apparently formed by modified spinules 

 or granules, are also found in certain of the Valvulosa. Sometimes 

 such pedicellariae are found associated with larger valvular pedicel- 

 lariae on the same specimen, as in the genus Nymphaster, and in a 

 few other genera. 



The writer, in a revision of the classification of the Asterioidea, 

 in 1899, proposed a rearrangement of the families and subfamilies. 

 That general arrangement is here adopted, but with various changes 

 made necessary by subsequent discoveries.' 



Order PHANEROZONA. 

 Suborder I. VALVULOSA Verrill = VALVATA Perrier 

 (sense extended). 

 Family I. OPHIDIASTERWAi Verrill, 1867 = LinckiadcF 



Perrier, 1875. 

 Family II. VALVASTERIDJE Fisher, 191 1. 

 Family III. ASTEROPIDJE Fisher, 191 1. 

 Family IV. OREASTERIDM Fisher = Pentacerotidce Gray 



(restricted). 

 Family V. MIMASTERIDjE Verrill. 



Family VI. GONIASTERIDM Forbes (restricted), includes 

 Anthencidcr Perrier (restricted). 



'Dr. Fisher (op. cit., 191 ifc) has adopted a very similar arrangement of the 

 families and subfamilies, with several changes, which are here mostly ac- 

 cepted. Some small extralimital groups are not included in this table. 



