Tlie marine Carboniferous of Nortli-east Greenl. and its Bracliiopod Fauna. 575 



(PI. 15, Figs. 6—7); the size, too, is difTerent, the specimens in ques- 

 tion attaining a width of only 11 — 13 mm., while Tscherxyschew's 

 figures have a width of 18 mm. 



N:o 12. Reticularia lineata Martin. 



For synonyms see Tschernyschew 1902, p. 193. 



In the free-lying boulder N:o 15^, of fine-grained, light limestone 

 from the Mallemukfjæld, there was obtained an imperfect specimen 

 af a ventral valve, with the umbonal region and the area well pre- 

 served, which I consider I can refer to this species. The specimen 

 when entire has measured about 22 mm. in width, 17 mm. in length 

 and 12 mm. in thickness. 



The species is widely distributed, both horizontally and verti- 

 cally. 



N:o 13. Strophalosia sp. hidet. N:o 1. 



PI. XXVIII, Fig. 7. 



A specimen of a Strophalosia, which I did not succeed in work- 

 ing out from the rock, will now be described, in spite of the fact 

 that it is impossible even approximately to determine its relation- 

 ship to forms already described. The stratigraphical distribution of 

 the genus Strophalosia, however, is so definite, appearing first in 

 any great number in the Upper Carboniferous beds, and with its 

 greatest distribution in the Permian formation, that the occurrence 

 here of its species is worthy of mention. 



In form, the shell is rounded triangular, with the length and 

 width equal, and with the greatest wddth near the anterior margin. 

 The ventral valve is fairly evenly arched, the arching being increased 

 in the anterior portion ; Ihere is visible here a very faint sinus, too. 

 The dorsal valve is concave, adhering pretty closely to the form of 

 the ventral valve and, consequently, giving a fairly small visceral 

 room. The length of the shell is about 18 mm., the width being 

 about the same; the thickness of the shell is about 7 mm., and the 

 distance between the valves about 4 mm. The hinge-line is straight 

 and fairly short (about 6 mm.) and the beak has probably been 

 truncated and did not project beyond the hinge-line. The shell 

 is characteristically sculptured; the ventral valve is covered with 2 

 to 4 mm. long spines which seem to be arranged in radiating rows 

 with intermediate spaces of from 1.^/2 to 2 mm. distance, while in 

 the rows themselves, the spines have a distance from each other of 

 about 2 mm. The spine-bases are almost circular, forming a minute 

 pustle. The dorsal valve is irregularly wrinkled, and is provided 

 with very fine striæ of growth. 



43* 



