296 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 



Figs. Z-Q.— Promo palxaster dyeri (Meek) (also see plates 18 and 25). 



3. One of the interbrachial areas with the ossicles displaced and the 

 adjoining adambulacral plates with their spines, X 4. 



4. Madreporite X 4. The rest of the plate is covered. 



5. Two abactinal spines, X 7. 



6. Five different abactinal ossicles, X 7. 

 All drawn from the holotype. 



Upper Ordovicic (Maysvillian). Cincinnati, Ohio. 

 Dyer collection of the Museum of Comparative Zoology, Harvard Uni- 

 versity (No. 13). 



Plate 21. 



Fig. 1. — Promopalseaster magnificus (Miller) (also see plates 22 and 23). 



Photograph, natural size, of the actinal side of one of the cotypes. This 

 Bpeci nen is probably the best preserved of Paleozoic starfishes and is one 

 of the largest species. 



Upper Ordovicic (Richmondian). Near Waynesville, Ohio. 



Harris collection of the United States National Museum (Cat. No. 40883). 



Plate 22. 



Fig. 1.— Promopalseaster magnificus (Miller) (also see plates 21 and 23). 



Abactinal side of the same specimen illustrated on plate 21. 



Plate 23. 



Figs. 1-3. — Promopalseaster magnificus (Miller) (also see plates 21 and 22). 



1. Camera lucida drawing X 3.5 of an interbrachial area. Additional 

 tube-feet probably also came out at the junction of the forked crests. 



2. Camera lucida drawing X 4 of the actinal area of one of the rays 

 toward the distal ends. Large adambulacrals bound the rays distally, 

 while the smaller pieces outside are the infi-amarginals. 



3. A distal portion of the abactinal area, X 3.5. 

 All drawn from the cotypes. 



Upper Ordovicic (Richmondian), Near Waynesville, Ohio. 



Harris collection of the United States National Museum (Cat. No. 

 40883). 

 Fig. 4. — Neopalxaster crawfordsvillensis (Miller) (also see plate 13). 



Camera lucida drawing X 4 of the abactinal area of the holotype. Ac- 

 cessory disk pieces are drawn in; in the specimen they are all displaced. 

 The madreporite should be more finely striate. In places the dorsal 

 skeleton is lost, exposing the ambulacrals. 



Mississippic (Keokuk). Crawfordsville, Indiana. 



Harris collection of the United States National Museum (Cat. No. 

 60607). 

 Figs, b-1 .—Petr aster spedosus (Miller and Dyer) (also see plates 26 and 27). 



5. The ambulacral, adambulacral and inframarginals of a ray at its 

 mid-length, X 4, Seen from the actinal side. 



6. Inframarginal, accessory interbrachial, and adambulacral pieces, X 4, 

 Seen from the dorsal side. 



7. Ambulacral and adambulacrals, X 4. Seen from the dorsal area. 



