NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 123 



Page 



Fig. 21. Blountia lata (Resser) 57 



Rubber impression of internal surface of cranidium, x5 (coll. cnn/3) ; 

 U.S.N.M. 144597, plesiotype. 

 Figs. 22-26. Maryvillia arion Walcott 59 



22, 23, Dorsal and lateral views of exfoliated cranidium, x2. 24, Py- 

 gidium, xl-5. 25, Exfoliated pygidium, xl-5 (coll. cnm/2) ; U.S.- 

 N.M. 144603, plesiotypes. 26, Partly exfoliated pygidium, X2 (coll. 

 cnn/1) ; U.S.N.M. 144604, plesiotype. 



Plate 10 



Figs. 1, 2. Blountia hristolensis Resser 58 



1, 2, Dorsal and lateral views of exoskeleton lacking free cheeks, x4 

 (coll. cnp/17) ; U.S.N.M. 144600, plesiotype. (See also pi. 11.) 



Figs. Z-7. Blountia mimula Walcott 59 



3, Cranidium, X3. 4, 5, Dorsal and lateral views of cranidium, X3. 6, 

 Exfoliated pygidium, X3. 7, Pygidium, X3 (coll. Oder No. 2) ; U.S.- 

 N.M. 144602, plesiotypes. 



Fig. 8. Glaphyraspis ornata (Lochman) 41 



Rubber cast of external impression of exoskeleton in shale, XlO (coll. 

 Oder No. 3) ; U.S.N.M. 144551, plesiotype. (See also pi. 11.) 



Figs. 9-17. Glaphyraspis parva (Walcott) 40 



9-12, 14, Cranidia, x7.5. 13, Free cheek, X5. 15-17, pygidia, X5 (coll. 

 cno/15) ; U.S.N.M. 144550, plesiotypes. 



Figs. 18-22. Glaphyraspis oderi Rasetti, n. sp 41 



18, Cranidia, the one at left being the holotype, X7.5, U.S.N.M. 144553. 

 19, Lateral view of holotype cranidium. 20, Cranidium, x7.5. 21, Free 

 cheek, x7.5. 22, Pygidium x7.5 (all specimens from coll. Oder No. 2; 

 U.S.N.M. 144554, paratypes. 

 Figs. 23-25. Pseudagnostus communis (Hall and Whitfield) 39 



23, Exfoliated cephalon, x4. 24, 25, Exfoliated pygidia, x4 (coll. ens/ 

 2) ; U.S.N.M. 144547, plesiotypes. 



Plate 11 



Figs. 1-8. Aphelaspidella macropyge Rasetti, n. gen., n. sp 96 



7, 8, Dorsal and frontal views of cranidium, x3 (coll. cnr/4) ; U.S.N.M. 

 144681, holotype. 1, 2, Cranidia, x3. 3, 4, Pygidia, x2. 5, 6, Free 

 cheeks, X2 (coll. cnr/4) ; U.S.N.M. 144682, paratypes. 



Figs. 9-12. Blountia hristolensis Resser S% 



9, 11, Cranidia, X4. 10, 12, Pygidia. X4 (coll. cnp/14) ; U.S.N.M. 

 144601, plesiotypes. (See also pi. 10.) 



Figs. 13, 14. Glaphyraspis ornata (Lochman) 41 



13, Pygidium, x7.5. 14, Cranidium, x7.5 (U.S.G.S. coll. 2804) ; U.S.- 

 N.M. 144552, plesiotypes. (See also pi. 10.) 



Figs. 15-21. Aphelaspis arsoides Rasetti, n. sp 94 



15-17, Dorsal, frontal, and lateral views of cranidium, X4 (coll. cns/2) ; 

 U.S.N.M. 144677, holotype. 18, 19, Cranidia, X4 (coll. cns/2) ; U.S.- 

 N.M. 144678, paratypes. 20, 21, Free cheeks, X4 (coll. cnt/4) ; U.S.- 

 N.M. 144679, paratypes. (See also pi. 12.) 



Plate 12 



Figs. 1-17. Aphelaspis camiro (Walcott) 83 



1, 2, Dorsal and frontal views of cranidium, X3. 3-5, Dorsal, lateral. 



