Pleurocystites squamosus (Billings) mut. matutina nov. 



Page 27 



Specimen (paratype) preserving portion of anal side; the 

 arrangement of the plates is drawn too regular, x 2. 



Specimen (holotype) showing the thecal plates and two pectin- 

 ated rhombs, the lower one of which is shortened by crush- 

 ing, x 2. 



Specimen (paratype) showing three pectinated rhombs and por- 

 tions of the two arms. Natural size. 



Specimen (paratype) preserving two pectinated rhombs and 

 showing the structure of the armlets. The plates are mostly 

 crushed and indistinctly shown. A few plates of the anal 

 side have been forced through a break and are seen on the 

 thecal side, x 2. 



Ordovician : Glens Falls limestone, South Glens Falls, N. Y. . 



Clarkeaster perspinosus nov. 

 Page 30 

 (See pi. 6, fig. 1 ; pi. 7> % s - l and 2 ) 

 Portion of actinal or ventral side of ray, showing the- ambulacral 

 furrow and ambulacral plates with their crests and podial 

 openings or depressions appearing as faint circles between the 

 crests, the adambulacras plates and the outer series of 

 large inframarginal plates bearing spines, x 5/2. 

 » Portion of actinal or ventral side of ray near tip of ray; the 

 ambulacral groove is closed and only the adambulacral and 

 inframarginal plates are seen, x S'A- Drawing from gutta- 

 percha squeeze of original mold. 

 Devonian: Chemung beds, Avoca, Steuben county, N. Y. 

 The originals of all figures are in the New York State Museum 



158 



