BRACHIOPODA. 473 



lliillina saffordi.l 



deltidial plates, characters also common to the Kampylopegmata, it seems natural 

 to expect that the earliest members of this suborder should have impunctate shells 

 as their immediate ancestors, the Rhynchonellidte. We find that the species of Hallina 

 of the Lower and Upper Silurian are impunctate, but that punctate Kampylopegmata 

 are already present in the Lower Helderberg, where the other type of shell structure 

 of this suborder is no longer met with. 



HALLINA SAFFORDI W. and S. 



. PLATE XXXIV, FIGS. 55-58. 



f 



1892; April 1. Hallina saffordi W. and S. American Geologist, vol. ix, p. 292. 



Shell very small, rostrate, regularly elongate oval, striate and evenly biconvex. 

 Ventral valve somewhat more convex than the dorsal. Point of greatest elevation 

 about mid-length, slightly carinated, but otherwise evenly convex in all directions. 

 Beak strongly incurved, but not in contact with the umbo of the dorsal valve, with 

 a small pedicle opening in the apex, which is partially surrounded anteriorly by 

 incomplete deltidial plates. Teeth well developed and supported by delicate, strongly 

 oblique, dental plates; other interior characters undefined. 



Dorsal valve evenly convex, with a very shallow sinus in the anterior half. 

 Brachial supports straight from the crural plates for a short distance forward, then 

 bend backwards and laterally, turn and proceed anteriorly to within a short distance 

 beyond mid-length and nearly parallel to each other, where they again turn rather 

 abruptly upward and inward, joining medially at a point which is about half the 







length of the brachia. Thin sections do not show strongly thickened crural plates, nor 

 a median septum amalgamated with the former, as is so common in terebratuloids. 



Surface marked with from fifteen to twenty subangular striae, which terminate 

 on the posterior third of the valves; no concentric lines of growth observable. Shell 

 structure fibrous and impunctate. 



This common little shell occurs in association with Leperditia fabulites, Scenidium 

 anthonensis and Rafinesquina minnesotensis. The only species, with which it is likely to 

 be confounded, if the exterior alone is taken into account, is Zygospira recurvirostra. 

 In the latter, however, the striae are more prominent and numerous and extend to the 

 beak on each valve, while in Hallina saffordi they are obsolete on the posterior third. 



Named after Prof. James M. Safford, Nashville, Tenn. 



Formation and locality Common in the "Glade limestone" at Lebanon, Tennessee, where they 

 were discovered by Mr. E. O. Ulrich several years ago. Also near the top of the Birdseye limestone at 

 High Bridge, Kentucky. 



Types in the collection of Charles Schuchert. 

 Mus. Reg. No. 8237. 



