NO. 4 



ziesenhenne: new eastern pacific sea stars 



201 



and very- large, conspicuous terminal plate instead of a pentagonal disk 

 and small inconspicuous terminal plates. 



It differs from the northern Pacific Leptychaster (Parastropecten) 

 anomalus Fisher by the following characters : 



L. (P.) stellatus 



Paxillar spinelets coarse, clavate. 

 Central paxillar spinelets 1 or 2. 

 Peripheral paxillar spinelets up- 

 ward of 9. 



L. (P.) anomalus 



Paxillar spinelets slender, terete. 

 Central paxillar spinelets 3 or 4. 

 Peripheral paxillar spinelets up- 

 ward of 10. 



Ambulacral spines proximally 4, Ambulacral spines proximally 5 or 



rarely 5, distally 3. 



Furrow margin of adambulacral 

 plate angular. 



Actinal spinelets clavate, less nu- 

 merous. 



Terminal plate large and conspicu- 

 ous. 



Disk stellate. 



Adambulacral plates shorter. 



First adambulacral plate com- 

 pressed. 



Adults have 18 superomarginals, 

 26 adambulacrals. 



6, distally 4 or 5. 



Furrow margin of adambulacral 

 plate convex. 



Actinal spinelets slender, tapering, 

 numerous. 



Terminal plate small and incon- 

 spicuous. 



Disk pentagonal. 



Adambulacral plates longer. 



First adambulacral plate not com- 

 pressed. 



Adults have 16 superomarginals, 

 29 adambulacrals. 



The name stellatus has reference to the long, narrow rays in contrast 

 to the usual short-rayed, pentagonal forms. 



Benthopectinidae 



Genus LUIDIASTER Studer 



Luidiaster californicus, new species 



Plate 31, Figs. 4-5; Plate 32, Figs. 1-7 



Description. — Rays 5, R=87 mm., r=16 mm., R=5.43 r. Breadth 

 of ray at base 19 mm. Abactinal surface of the disk and basal portions of 

 the rays slightly swollen. Abactinal integument composed of large circu- 

 lar plates interspaced with numerous small, irregular, round and elon- 

 gated plates. A section of integument cleared in xylene revealed the plates 

 as irregularly arranged and close together, but not in actual contact. The 

 smaller plates serve as connectives between the larger ones, and the papu- 



\0 



