58 PALAEONTOLOGY OF NEW YORK. 



Obolella ;in(l Lingulella, Ford), which show a close agreement in the internal 

 characters of these species. 



In the pedicle-valve the lateral scars make the long sweeping curves so 

 characteristic of Obolella, while the centrals, more or less coalesced, produce a 

 broad, somewhat tripartite scar. In 

 the brachial valve of L Ella, appear JB^a ^I 

 to be two diverging lateral scars, ex- 

 tending about one-half the length of the 

 shell, and incurving at their anterioi- ^"'»"'''""^f^'^«:'^\!f^^™';,^^'^ 



«.-.,1o +rnt-oiTl tlTO i.ir>i-o nnnwnipiimi* •lull FlO. 19. Dorsal aspect, showing pedicle-area. FiG. 20. Inter- 

 enUStOWaiU tnemoie conspicuous ami „ai castor pciliclevalve. fig. 21. internal cast ofl^niclualvalve. 



apparently compound central scar. Essentially the same characters are seen in 

 the brachial valve of L. ccRlata, accompanied by posterior lateral scars, which 

 occupy a position homologous with the terminal scars in the Trimerellids. An 

 additional character is given to the muscular scars of the brachial valve in Mr. 

 Walcott's figures of his .species, Lingiilella Granvillensis* in which there 

 appears, near the center of the shell, a faintly defined, bilobed scar, continued 

 anteriorly into an oval impression. These represent the " anterior adductor 

 mu.scular scars, and aLso what may have been the adjustor muscular scars "f 

 or the anterior laterals and the centrals of Lingula. This feature constitutes 

 a conspicuaus difference from the obolelloid character of these impressions 

 in the brachial valves of the other species cited, and it will be important 

 to verify the character. The pedicle-valve of this species shows the straight (?) 

 diverging ridges similar to those in L. Dawsoni-X 



Figures have been given by Mr. Davidson, showing the muscular scars in the 

 species L. ferruginea, Salter,§ and L. lepis, Salter.|| In both these species the 

 elongate, more or less curved laterals are apparent, enclosing a compound central 

 scar not essentially differing from that in L. Ella, though more sharply outlined. 



* Amei-ican Journal of Science, voL xxxiv, p. 188, iil. i, iijj. 15 a. 1887. 



t 'Walcott, loc. cit. 



I By the fiivoi- of Mr. G. V. Mattukw wo ai-e enabled to give an origiu-al figure of the interior of this 

 species taken from the specimen rejiresented in his " Ilhistrations of the Fauna of the Saint John Group," 

 No. 3, )il. V, fig. 9 d (Trans. Roy. Soc. Canada, Sec. iv. ISS.")). We have not observed the sharply defined 

 muscular inijiressions represented by Mr. Maithew. 



§ Mon. Brit. Sil. Brach., pi. xlix, figs. 33a, Z'm. 1871 ; and Geol. Mag., vol. v, No. 7, pi. xv, fig. 3a. 1868. 



I Mon. Brit. SiLBnich.,pl. .xlix, fig. 31a. 1871 ; and Geol. Mag., vol. v, No. 7, pi. xv, fig.s. llandlla. 1868. 



