168 Mr. W. K. Fisher on new Pterasteridae 



c. Paxilhe with high pedicel and 5 to 15 

 (5 to 7 in Alaskan specimens) spines ; 

 superoral spine slender, cylindrical ; 

 muscle-hands connecting - tips of paxillar 

 spinelets ; aperature slits small ; oral 

 spines 6 or 7 ; no deposits in supra- 

 dorsal membrane; lateral fringe not 



defining ambitus pulvillus, Sars. 



cc. Paxillae low, with low pedicel and 5-7 

 short spines ; superoral spine with 3 

 sharp edges; no muscle-bands connect- 

 ing tips of paxillar spinelets ; aperature 

 slits unusually large ; oral spines 5 ; 

 in supradorsal membrane deposits in the 

 form of branched rods ; lateral fringe 



denning ambitus temnochiton, sp. n. 



bbb. Oral spines 3, the series independently 



webbed ; abactinal surface not much 



elevated and not at all warty multispinus, Clark. 



Pteraster trigonodon, sp. n. 



Hays 5. R = 30 mm., r=16 mm., 11=187 r; breadth of 

 ray at base 18 mm. General form stellate with angular 

 interbrachial arcs. Disk moderately high ; vertical diameter 

 about two-thirds breadth of ray. Supradorsal membrane 

 thin, without definite reticulations; calcareous deposits 

 abundant, in the form of irregular spiny rods; spiracula 

 numerous, large; pseudopaxillse with high pedicels and 6 

 divergent spines ; 5 adambnlacral and 5 webbed marginal 

 mouth-spines; aperature papilla very broad; superoral spine 

 very large, sharp, and 3-edged ; actinolateral membrane 

 narrow, not defining ambitus. 



Off iSanta Cruz Island, California, 447 to 510 fathoms. 

 Bottom, black mud. 



Pteraster marsippus, sp. n. 



In general appearance and proportions similar to jordani ; 

 differs in having 3 shorter paxillar spines, sparse calcareous 

 deposits in the form of simple straight rods of small size in 

 supradorsal membrane, proximal ly 5 adambulacral spines 

 (far along ray only 4), and especially in having the aperature 

 papilla partially tented over by a membrane passing from one 

 comb to the next, and merging outwardly with the actino- 

 lateral membrane. A shallow side pocket opening mesially 

 is thus formed, at the mouth of which is the aperature papilla. 

 No spiracles. 



Type. R=100 mm., ?- = 40 mm., R = 25 r; breadth of 

 ray at base 45 mm. ; li varies to 1*8 r. 



