398 BULLETIN 76, ITNITED STATES NATIONAL MUSEUM. 



Plate 57. 



Fig. 1. Peclinaster agassizi cvoplus; papularium drawn from inner side, showing disposition of plates; 

 r-r, radial line; />, papulse, X 8. 



2. Gephyreaster smifti; specimen from station 4784, mouth plates, showing the inner angle or face 



toward actinostome, the peristomial membrane (per) below, the vertical suture between 

 the plates (s), the median tooth ((/), and the peculiar marginal series of spines which 

 descend the sides of plate nearly to peristome; the spinelets nearest the actinostome are 

 the lightest; the strictly marginal series of spinelets bordering furrow are marked a, X 6. 

 2a. Same; median tooth of type. 26. Same; side view of abactinal plates from radial 

 line near base of ray, type, X 10. 2c. Same; larger spines from inferomarginals, X 20. 



3. Mediagter tenellus; fourth adambulacral plate, X 10. 3a. Side view of furrow spine. 36. Pedi- 



cellaria on first adambulacral plate. 3f. Pedicellaria from an actinal intermediate plate 

 just back of mouth plates, X 10. 3<i. A large paxilla from proximal radial region of dorsal 

 surface, X 10. 



4. Pseudarchaster pusillus; seventh adambulacral plate of type, X 10. 4a. Same; adambulacral 



plates showing pectinate pedicellaria;. 



5. Pseudarchaster parelii; specimen from station 3225, ninth adambulacral plate; specimen with 



very coarse spinelets, X 8. 



6. Pseudarchaster parelii alascensis; twelfth adambulacral plate, type, X 9. 



7. Pseudarchaster dissonus; third, fourth, and fifth adambulacral plates with adjacent pedicellarise; 



ad, adoral side of plate; x, jaw of pedicellaria on adambulacral plate; int, intermediate 

 plate, the three small spinelets being on the actinal intermediate plate and bordering the 

 furrow, X 5. 7a. Same; second, third, and fourth adambulacral plates of specimen from 

 station 3601, to show slightly different pedicellariie; adoral side of plates to left, X 10. 



Plate 58. 



Fig. 1. Ceramaster arctims; specimen from station 3212, two adambulacral, and two adjacent interme- 

 diate plates {int), small specimen, X 10. 



2. Ceramaster clarki; eighth and ninth adambulacral plates, X 10. 2a. Same; actinal intermediate 



pedicellaria, near above plates, X 10. 26. Same; crown of radial plate showing pedicel- 

 laria, X 10. 



3. Ceramaster leptoceramus; adambulacral plate, X 10. 3a. Same; one of the radial plates with 



three secondary paxilla; from proximal radial region, X 15. 



4. Cnjptopeltaster lepidonotiis; third and fourth adambulacral and an actinal intermediate plate; 



adoral side to the left, X 5. 4a. Same; two primary plates from abactinal surface, radial 

 region, one with a tubercle, the other with characteristic bivalved pedicellaria; between 

 the two are numerous secondary ossicles, X 8. 



5. Eippasteria lieathi; eleventh adambulacral and adjacent actinal intermediate plate, X 5. 5a. 



Same; abactinal plates, proximal radial region; specimen partly dry and papulae shrunken, 

 X 5. 



6. Eippasteria leiopelta; two adambulacral and an actinal intermediate plate, partly dry, X 10. 



7. Poraniopsis inflata; three adambulacral plates from near middle of H, the furrow spines above, 



and three views of actinal adambulacral spines, below; on the right the actinal epine is 

 bent so as to be parallel with furrow spines, of which tlie upper or grooved side is shown; 

 type, X 5. 7a. Same; from station 4362, similar vaew to above from a variety with slender 

 adambulacral spines, X 5. 



8. Poraniovsis inflata flexilis; type; three adambulacral spines; /, furrow and a, subambulacral 



spine, with flange of tissue; X 5. 



Plate 59. 



Fig. 1. ilediaster xqualis; abactinal plates from proximal radial region, showing internal connecting 

 ossicles (dotted); p, papula;; r, radial series, X 8. la. Same; bottom of a radial plate; 

 16. Side view of same. Ic. Same; eighth to tenth ambulacral plates showing the small 

 superambulacral ossicles dotted; am, ambulacrals; ad, adambulacrals; int, actinal in- 

 termediate plates; sup, superambulacrals, X 8. 



