PLATE CIX. 



Fig. I. Orthasterias tanneri Verrill. Cotype. Actinal side of disk, to 



show jaws and peroral spines; X 2^. 



Fig. la. The same specimen. Dorsal side of disk, showing spines and 



pedicellariae ; X3. 



Fig. lb. The same specimen. Section of a ray, showing inner surface 



of skeleton; cut through ambulacral plates and flattened 

 out; a, a, ambulacral plates; ad, ad, adambulacral plates; 

 b, b, peractinal plates; m, m, inferomarginals ; m', m', 

 superomarginals ; d, d, dorso-lateral plates and transverse 

 connective ossicles; s, s, adambulacral spines; c, c, median 

 radial or carinal plates ; X 25^. 



Fig. 2. O. Columbiana Verrill. Type. Transverse section of a ray; 



a, a, ambulacral plates; ad, ad, adambulacrals ; b, b, per- 

 actinals; m, m, inferomarginals; m', m', superomarginals; 

 d, d, dorso-lateral plates and transverse ossicles ; c, carinals ; 

 X2. 



Figs. 2a, 2b. The same specimen. Two parts of a transverse section of a 

 ray, split through the ambulacral plates and flattened out, 

 to show inner surface. Lettering as in fig. ib, except that 

 d, d; d" d' ; d'*, d" show the three rows of dorso-lateral 

 plates ; X 2. 



Fig. 3. Patiria miniata (Brandt). Central part of disk and madreporic 



plate, with spinules removed ; X 2. 



FlG. 4. Enoplopatiria siderea Verrill. Type. Dorsal view of middle 



of a ray with spinules removed ; X 2. 



(230) 



