A CARBONIFEROUS FAUNA FROM NOWAJA SEMLJA. 159 



Genus Spirifer J. Sowerby. 



Spirifer cf. bisulcatus J. de C. Sowerby. 



The specimen is too incomplete for a satisfactory determination, but it certainly 

 belongs to the group of Spirifer bisulcatus J. de C. Sowerby. 



Cf. Spirifer triradialis Phillips. 



One specimen, measuring 6*5 mm. in length and 3'5 mm. in breadth, should possibly 

 be placed here, but its true affinities must remain doubtful, on account of its fragmentary 

 condition. 



Genus Martiniopsis Waagen. 

 Martiniopsis ? sp. (PL I. fig. 12.) 



Two pedicle-valves of a Spiriferid show a peculiar combination of characters which 

 might determine its reference to either of the two genera Spirifer or Martiniopsis, 

 according to the view taken as to the value of these characters, considered individually. 



The outline is sub-rhomboidal, with length exceeding width. The larger specimen 

 is 18 mm. long and 16 mm. wide : it is not very convex and has gently sloping sides. 

 The area appears to be small and the beak is not much incurved. The sulcus is narrow 

 and does not increase in width towards the anterior margin. The surface — excepting 

 the cardinal slopes, which are smooth — is ornamented by ten broad, very fiat ribs, separ- 

 ated by narrow sulci. One rib occupies the bottom of the median sulcus. The external 

 layer is minutely pitted, as in Martiniopsis and in most species of Martinia. Inter- 

 nally, the shell is characterised by two well-developed dental plates. 



The true generic affinities of this form cannot be determined, owing to the brachial 

 valve (typically septate in Martiniopsis) being unknown ; but it is interesting to note 

 that the elongate shape, the median sulcus, and the ribbing of the shell are characters 

 not included in Waagen's diagnosis of his genus Martiniopsis, under which the present 

 form ought to be placed, on account of its pitted surface and small area. Even in the 

 event of the latter view being proved correct, this would not be the first record of an 

 elongate and ribbed Martiniopsis* 



Genus Martinia M'Coy. 

 Martinia sp. (cf. Spirifera planata Phillips). (PI. I. fig. 14.) 



A pedicle-valve, 11 mm. in length and 10 mm. in breadth, is externally very much 

 like "Spirifera" planata Phillips, as redescribed by Davidson (loc. cit., p. 26, pi. vii. 

 figs. 25-36), with this difference, that the sulcus is more sharply defined and ornamented 

 by three ribs only, instead of four or five. 



* Compare, for instance, Martiniopsis aschensis, Tscherntschew, loc. cit., pi. 1., fig. 4. 

 TRANS. ROY. SOC. EDIN., VOL. XLVII. PART I. (NO. 7). 24 



