290 ' BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 



PLATE 4. 



FIG. 1. Hudsonaster narrawayi (Hudson) (also see plates 1 and 2). 



A camera lucida drawing X 8 of the actinal side. The granules are 

 drawn somewhat too strongly. 



Middle Ordovicic (Black River). St. Paul, Minnesota. 



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

 60602). 

 FIG. 2. Hudsonaster milleri, new species. 



A diagram, considerably enlarged, of an axillary area from the actinal 

 side. 



Middle Ordovicic (Trenton). Fayette County, Kentucky. 



Collection of the State University of Kentucky. 

 FIG. 3. Mesopalxaster (?) lanceolatus, new species. 



Camera lucida drawing of one ra> from the actinal area, X 2. The 

 central furrow in the ambulacrum is decidedly V-shaped. 



Upper Ordovicic (Utica). Near Rome, New York. 



Collection of Peabody Museum, Yale University. 

 FIG. 4. Australaster giganteus (Etheridge). 



An axillary area and part of two rays somewhat reconstructed from the 

 original figure. Natural size. Note the single very large axillary plate, 

 the enlarging adambulacrals, and the diminishing inframarginals. 



"Permo-Carboniferous" (Lower Marine). Parley, Northumberland 

 County, New South Wales. 



Collection of the Mining and Geological Museum, Sydney. 



PLATE 5. 



FIGS. 1 and 2. Hudsonaster matutinus (Hall) (also see plates 2 and 3). 



1. Camera lucida drawing X 3.5 of the actinal side of one of the speci- 

 mens photographed on plate 2, fig. 2. 



Middle Ordovicic (Trenton). Near Newport, New York. 

 Collection of Museum of Comparative Zoology, Harvard University 

 (No. 26). 



2. Camera lucida drawing X 4.5 of the abactinal area of a specimen in 

 which the ossicles are somewhat displaced. 



Middle Ordovicic (Trenton). Lachine, near Montreal, Canada. 

 Collection of the United States National Museum (Cat. No. 60603). 

 Collected by W. R. Billings. 



PLATE 6. 



FIGS. 1 and 2. Hudsonaster incomptus (Meek). 



1. Camera lucida drawing X 4 of the actinal side. 



Upper Ordovicic (Richmondian). Near Waynesville, Ohio. 



Harris collection of the United States National Museum (Cat. No. 40882). 



2. Camera lucida drawing X 4 of the abactinal area in a well preserved 

 specimen. The anal opening may have been in the first circle of small 

 plates adjacent to the centro-dorsal piece and in the same interradius as 

 the madreporite. 



Upper Ordovicic (Richmondian). Near Waynesville, Ohio. 



Harris collection of the United States National Museum (Cat. No. 40882). 



