SPIRIFER RADIATUS Sowerby (Packs 3S2-38G) 



Figure 9. — A cardinal view; showing a similar stage of develop- 

 ment of the deltidiiim ; from an individual which has notattained normal 

 full-growth. 



Figure 10. — The youngest giowth-stage observed. 



Figure 10a. — Outline profile of the same. 



Figure 11. — Dorsal view of a normal adult. 



Figure 11«. — Proiile of the same. (2S(//, Ann. llepl. N. Y. Stale 

 Mux. Nat. Hist., pi. 24, figs. 20, 25.) 



ATRYPA RETICULARIS Linn/eus (Pages 350-360) 



Figure 12. — The incipient shell ; having a length of 2.2.") mm. The 

 deltidial plates have already begun to form, and the shell has developed 

 two growth-lines. 



Figure 12a. — Outline profile of the same. 



Figi'RE lo. — Ventral view of a full-grown individual. 



Figure 18a. — Profile of the same. (■2>ilh Ann. Rrpl. N. Y. State 

 Mus. Nat. Hilt., pi. 25, figs. 40, 47.) 



F'iGURE 14. — A series of outlines of the anterior margin of the valves; 

 showing the rapid increase in plications and the reversion from the em- 

 bryonic fold and sinus to the sinus and fold of maturity. 



Figure 15. — The deltidial characters of the specimen represented in 

 figure 12. 



Figure 15a. — Outline profile of the same. 



Figure 16. — Similar view of a specimen measuring 3 X 3 mm. 



F^iGURE ICa. — Outline profile of the same. 



Figure 17. — Similar view of a specimen measuring 3.5 x 4 mm. 



Figure 17a. — Outline profile of the same. 



F^iGURE 18. — Similar view of a specimen measuring 8x7 mm. 



Figure 18a. — Outline profile of the same. 



Figure 19. — Similar view of a sjiecimen measuring 21 X 20 mm. 



Figure 19a. — Outline profile of the same. 



Figure 20. — Similar view of a full-grown specimen measuring 

 24 X 22 mm. 



F^igure 20a. — Outline profile of the same. 



