10 LINNARSSON. BRACHIOPODA 01- THE PARADOXIDES BEDS. 



Forchhammeri tliey are most numerous. particulurly in Westro- 

 gothia, where the limestone of tliat division is often replete 

 witli closely packed fragments of their valves. Even in Xerike, 

 Oland, and Jemtland some species oecur abundantlv in the same 

 division, while again in Scania thev are comparativelv scarce. 

 the Trilobites having a great predominance in the Andraruin 

 limestone of that provinee. In the other divisions the Brachio- 

 poda are not numerous, and most of the species found are iden- 

 tical with species occurring in the beds with Paradoxides Forch- 

 hammeri, or, at least, verv nearlv related to them. 



II. Descriptious of the Species. 

 Orthis Lindströmi n. sp. 



Pl. L pl. II. tigs. y— 12. 



Eotundato-(juadi'ate, wider than long, broadest anteriorly. 

 Hinge-line straight, less than the width of the shell; cardinal 

 angles rounded; front subtruncated or, sometimes, slightly in- 

 dented. Ventral valve -very gently convex. most so near the 

 beak, without fold or sinus; beak small; area low, dirccted back- 

 wards, but not distinctly seen in anv of the specimens obtained. 

 Dorsal valve rathcr decper than the opposite one, diA'ided lon- 

 gitudinally by a sinus, Avhich extends from the beak and ante- 

 riorly often becomcs obliterated. In the interiör of the ventral 

 valve the cardinal area is shallow, rhombic, usually marked 

 "svith concentric wrinkles; from its anterior margin there extend 

 on either side two parallel furrows, enclosing a slight ridge; 

 after liaving run parallel for a space, these furrows bend asuuder, 

 so that the two middle ones nieet in the median line, whereas 

 the two outer ones bend outwards and bäckwards, parallel to the 

 circumference of the valve; this feature is usually best seen in 

 the internal casts; outside the furrows tlierc is a space co- 

 vered with numerous, A^ery delicate, branched, radiating veins. 

 The spaces withiu the furrows are, on the contrary, smooth. Of 

 the dorsal vah'e I have not been able to obtain any good in- 

 teriörs; especially the hinge-margin is alwavs in a bad state of 

 preservation, as it sticks very härd to the rock bccausc of its 



