58 PALEONTOLOGY OF NEW YORK. 



Obolella and 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 M^^k //iV^^ 

 to be two diverging lateral scars, ex- 

 tending about one-half the length of the 

 shell, and incurving at their anterior LinauidiaEiu,\unani^vut&<iW. 



oiide fnwnrrl thp innrp Pnnsnipiinns niul FiG. 19. Dorsal aspect, showing pedicle area. Fio. 20. Intcr- 

 enUblOWaru ine moie COUbpiCUOUb aim nalcaslofpeiliclevalve. FiG.il.Iiitcrnalcastolbracliialvalve. 



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

 the brachial valve of L. celata, 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, Lingulella 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 

 muscular scars, and also what may have been the adjustor muscular scars "f 

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

 a conspicucous 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.f 



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. 



* Amui'icuti Jounial of Science, voL xxxiv, p. 188, pL i, tig-. 15 a. 1S87. 



t Walcott, loc. cit. 



I By tlio favoi' of Mr. G. V. Matthbw we are enabled lo jrive an oi-iginal figure of the interior of tliis 

 species taken from the sjieciinen represented in his "Illustrations of the Fauna of the Saint John Group," 

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

 muscular impressions lepresonted by Mr. Mattiikw. 



§ Mon. 13ril. .Sil. Bi-ach., pi. xlix, figs. 33o, 3oa. 1871 ; and Geol. Mag., vol. v, No. 7, pi. xv, fig. 3a. 1868. 



I Mon. Brit. Sil. Brach., pi. xlix, fig. 31a. 1871 ; and Geol. Mag., vol. v, No. 7, pi. xv, figs. 11 and 11a. 1868. 



