294 Raymond — Common Devonian Brachiopods. 



l'5 mm long have plications, the number increasing from 7 on a 

 specimen of that length to about 18 on a specimen 5'5 mm long. 



12 



Figure 12. — Trigeria lepida Hall ; series showing the growth of the deltid- 

 ial plates and the encroachment of the pedicle upon the ventral beak, x 8. 



Deltidial Plates. — None of the specimens less than 3 mm long 

 show any deltidial plates. In succeeding stages the plates 

 appear as narrow triangles, one on each side of the delthyrium, 

 and these triangles gradually become broader until they meet 

 at the base. In the meantime, the pedicle encroaches upon the 

 ventral beak so that an oval pedicle opening is formed in the 

 adult (figure 12). 



Eunella LincMaeni Hall. 

 Pal. N. Y., iv, 1867, p. 397, pi. 60, figs. 49-65. 



The list of changes in the form of this shell is not complete 

 enough to offer anything new, but there are one or two interest- 

 ing points in connection with the species. 



Pttnctbd. — On the dorsal beak of the smallest shell (l*17 mm X 

 •84r mm ) the first punctse can be seen, and their arrangement 

 agrees with that seen on the nepionic shell of Terebratulina 

 septentrionalis* The first pair of punctse is -07 mm from the 



13 



14 



15 



Figure 13. — Eunella Lineklaeni Hall ; part of the loop of an adult speci- 

 men, x 8. 



Figure 14. — Centronelliform stage of the loop, x 8. 



Figure 15. — Side view of specimen shown in Figure 14 ; shell broken 

 away to show the loop, x 16. 



beak, and in front of them, on the median line, is a third one. 

 Beyond this they are scattered sparingly over the surface for a 



* E. S. Morse, Memoirs Boston Soc. Nat. Hist., vol. v, No. 8, 1902, pi. 62, 

 fig. 15; also vol. ii, pt. i, No. 2, pi. 1, fig. 3. 



