NO. 2225. NUCULITES FROM THE MAINE SILURIAN— WILLIAMS. 31 



muscular scar and extending without interruption posteriorly as far as 

 the posterior scars. Ligament external, contained in a narrow groove 

 along the margin of the hinge. Anterior muscular scar deeply impressed, 

 separated from the cavity of the shell by a vertical or slightly oblique 

 clavicle or partition, extending about two-thirds the distance from the 

 beak toward the base. 



Posterior scar elongate, situated just below the termination of the hinge 

 crenulations. Just anterior to the posterior adductor are one or two 

 small retractor impressions. The cavity of the umbo also usually shows 

 three or four impressions of umbonal muscles. PaUial line simple. 



This genus differs very distinctly from Nucula in the anterior clavicle 

 and absence of cartilage pit. 



Examples: Nuculites oblongatus, plate xlvii, figures 1-12. Nucul- 

 ites triqueter, plate xlvii, figures 17-28.* 



NEW SPECIES FROM WASHINGTON COUNTY, MAINE. 



The following species of Nuculites have been recognized from the 

 faunules of the uppermost beds of the Edmunds formation (locahty 

 numbers 5.33.8 B, and 1443 D 7) and from the Leighton shale mem- 

 ber of the Pembroke formation (locality numbers 1.43.9 A, 1.45.6 A, 

 1.55.1 A, 5.34.7 A^, 5.44.2 A, 5.3.2 A, 5.3.8 F, E and W, 5.4.7 B, 

 5.25.4 B, 5.24.6 B). 



EDMUNDS POKMATION. 



Nuculites corrugatus, page 32, plate 11, figures 10, 18. 



N. subplanus, page 34, plate 11, figure 17; plate 12, figure 8. 



N. trescotti, page 35, plate 12, figure 1. 



N. lentus, page 46, plate 12, figures 6, 13. 



PEMBROKE FORMATION, LEIGHTON MEMBER. 



Nuculites corrugatus, page 32, plate 11, figure 12. 



N. amycus, page 43, plate 11, figure 5. 



N. battus, page 43, plate 11, figures 11, 13. 



N. galeus, page 44, plate 11, figures 1, 14, 19; plate 12, figm-e 2. 



iV. thyestes, page 41, plate 11, figure 8. 



N. atreus, page 40, plate 12, figure 3. 



N. chrysippus, page 39, plate 12, figure 5. 



N. speciosus, page 38, plate 12, figures 9, 18, 19. 



N. pelops, page 44, plate 11, figures 3, 7, 19. 



N. eurylochus, page 45, plate 11, figure 4. 



N. pholus, page 32, plate 11, figure 6. 



N. ladon, page 33, plate 11, figure 15. 



N. lichas, page 34, plate 11, figure 20. 



N. nessus, page 33, plate 11, figure 21. 



1 P»l. New York, vol. 5, part 1, Lamellibranchiata, 2, pp. xxvl, xxvii. 



