from the North Pacific. 169 



Near Attu Island, Aleutians, 135 fathoms. Bottom, coarse 

 pebbles. 



Pteraster coscinopep!us } sp. n. 



Stellato-pentagonal. R = 30 mm.,?-=21 mm., R = l*4 + r ; 

 breadth of raj, omitting lateral fringe 22 mm., with lateral 

 fringe 25 mm. Supradorsal membrane without special 

 muscle-bands connecting summits of spines, but with a fine 

 reticulation; spiracula very numerous, small ; no spicules; 

 paxillaj with high pedicels and 6 to 8 spines; actinolateral 

 membrane very wide, the free border defining entire ambitus ; 

 6 webbed adambulacral spinelets ; 1 very slender superoral 

 spine; 6 slender free marginal mouth-spines. 



Off San Diego, California, 339 fathoms. Bottom, mud. 



Pteraster tnnucchiton, sp. n. 



Rays 5. 11=21 mm., r=16 mm., K = l'3 + r; breadth 

 of ray at base, without lateral fringe 9 to 11 mm., with lateral 

 fringe 12 to 12'50 mm. General form stellato- pentagonal ; 

 interbrachial arcs shallow; lateral fringe defining ambitus ; 

 pseudopaxillse low, with 5 to 7 spines; no reticulation; 

 groups of spines independent and spaced ; scattered branched 

 irregular rods in membrane ; adambulacral spines 5 to 4 

 webbed, the outer standing perpendicular, not subparallel to 

 actinolateral membrane which is wide; aperatures long; apera- 

 ture papillae slender, sharp, with slightly convex aboral margin; 

 oial spines 5, slender, all 10 united by continuous membrane; 

 superoral spine sharp, 3-edged, much heavier than marginal 

 spines. 



Near Attu Island, Aleutians, 135 fathoms. Bottom, 

 coarse pebbles. 



Hymen aster. 



Three species occurring off the west coast of North America 

 are contrasted in the following synopsis : — 



a. AdamLulacral armature consisting of 1 spine- 

 let ; size very large ; paxilhe forming special 

 raised areas ; spiracula small, in definite 



circumscribed areas koehleri, sp. n. 



aa. Adambulacral armature consisting of more 



than 1 spinelet; spiracula not in definite 



circumscribed areas. 



b. Median radial paxillae very much reduced 



in size, with 1 to 3 basal lobes ; 5 rows 



of paxillse on ray ; adambulacral spinelets 



2 or 3 periesonotus, sp. n. 



