50 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



Fagre 

 Plate 7 



Figs. 1-6. Acidiscus hexacanthus Rasetti, new species 13 



1-3, Dorsal, frontal, and lateral views of cephalon, X3; U.S.N.M. 

 145989, holotype. 4, 5, Lateral and dorsal views of cephalon, X5. 

 6, Pygydium, X6. U.S.N.M. 145990, paratypes. 



Figs. 7-11. Serrodiscus spinulosus Rasetti, new species 33 



7-9, Lateral, dorsal, and frontal views of cephalon, XS; U.S.N.M. 

 146026, holotype. 10, 11, Dorsal and lateral views of pygidium, X5; 

 U.S.N.M. 146027, paratype. 



Figs. 12-18. Calodiscus reticulatus Rasetti, new species 24 



12-14, Dorsal, frontal, and lateral views of cephalon, X4; U.S.N.M. 

 146006, holotype. 15, Cephalon, X5, 16, Glabella of another specimen 

 showing ornamentation, XlO. 17, Lateral view of the same cephalon, 

 X4. U.S.N.M. 146007, paratypes. 18, Incomplete cephalon, showing 

 occipital ring and posterior border, X5 ; U.S.N.M. 146008, paratype. 



Plate 8 



Figs. 1-9. Litometopus longispinus Rasetti, new genus, new species . . 27 

 1-3, Dorsal, frontal, and lateral views of cephalon, X3; U.S.N.M. 

 146012, holotype. 4, 5, Lateral and dorsal views of cephalon, X4. 

 6, Pygidium, X2. 7, Pygidium, X2. 8, Lateral view of doublure of 

 the same pygidium, X5. 9, Pygidium, X3. U.S.N.M. 146013, para- 

 types. 



Figs. 10-19. Serrodiscus subclavatus Rasetti, new species 31 



10, 11, Dorsal and oblique views of cephalon, X4; U.S.N.M. 146022, 

 holotype. 12, 13, Dorsal and lateral views of cephalon, X3. 14, Por- 

 tion of same cephalon, showing ornamentation and characteristic 

 furrow parallel to posterior margin, X7.5. 15, Lateral view of 

 pygidium, X5. 16, Lateral view of pygidium, with portion of axial 

 spine restored, X4. 17, 18, Oblique and dorsal views of pygidium, 

 X4. 19, Cephalon with two thoracic segments attached, X3. U.S.N.M. 

 146023, paratypes. 



Plate 9 



Figs. 1-16. Bathydiscus dolichometopus Rasetti, new genus, new species . . 17 

 1-3, Dorsal, frontal, and lateral views of cephalon, X4; U.S.N.M. 

 145995, holotype. 4-6, Dorsal, frontal, and anterodorsal views of 

 cephalon, X3. 7, Portion of cephalon, XS. 8, Frontal view of the same 

 cephalon, X3. 9, 10, Posterior and lateral views of pygidium, X4, 

 exposing doublure. 11, 12, Dorsal and posterior views of pygidium, 

 X3. 13, Pygidium, X3. U.S.N.M. 145996, paratypes. 14-16, Lateral 

 dorsal, and posterior views of pygidium, X4; U.S.N.M. 145997, 

 paratype. 



Figs. 17-21. Calodiscus fissifrons Rasetti, new species 22 



17, Cephalon, XS; U.S.N.M. 146004, holotype. 18, 19, Incomplete 

 cephala, X4. 20, Small pygidium, XlO. 21, Pygidium, X5. U.S.N.M. 

 145005, paratypes. 



