3?»L^^rE VII. 



Page. 

 Fi;?. 1. Oi'.iiiis Miciiici.iM i-nr. Nf.vadknsis 03 



1. A khU: view of a lari;<' specimen. [Beak of ventral valve not quite arched enoiigli, 



and tlie lieigbt of the area of the dorsal valve not well shown, iu this figure.] 

 1 n. A dorsal view of same. [Figure makes the cardinal area look too wide.] 

 1 h. A side view of a smaller specimen. 

 1 c. A ventral view of same. [Posterior lateral striaj too straight in this figure and 1 a.] 



Fig. 3. Hr.MiPiiONrrKS ckenisthia (J2 



2. A ventral view of an accidentally distorted specimen. 



Tig. 3. PltODUCTU.S .SUBHOIiRIDUS 75 



3. A side view. 



3a. A front view of another specimen. 



3 h. A ventro-anterior view of another example. 



Fig. 4. PliODUCTU.S COSTATUS ? ? <J9 



4 An anterior view ; the shell being turned so as to show the irregularity of theeosta} 



on the anterior slope. 

 4 a. A side view. 

 4 6. A ventral view. 



Fig. 5. PUODIICTUS SEMIHETICULATUS <)9 



G. View of ventral valve. 



Fig. G. PnoDiiCTUs IVESI? C7 



G. An oblique side view of a large specimen distorted by pressure. 



Go. A ventral view of another specimen, with its ears and margins broken away. 



G (). An external cast of the dorsal valve, with some portions of the shell remaining near 

 the cardinal margin, showing the thick marginal ridge, and a part of the cardinal 

 process, with the small mesial ridge, which latter is divided near the cardinal pro- 

 cess, as in P. scahriiiiliis. 



Fig. 7. Pi!()i)uc-n;s Phattic.niani-s "- 



7. A ventral view of an imperfect specimen, with the ears and free margins broken 

 away. 



7 n. A side view of another imperfect specimen. 



Fig. 8. PltODUCTl'S SRMISTIilATUS 74 



B. An untero-ventr.al view. 



8 a. A side view of same. 



