The marine Carboniferous of North-east Greenl. and its Brachiopod Fauna. 561 



with Schwagerina princeps, found as boulder at Sophus Müller's Naze 

 (Eskimo dwelling-place, 80°55'). 



I name this new species after Mylius-Erichsen, the leader of 

 the Danmark Expedition, who, during the course of the great sledge- 

 journey towards the north, discovered this locality, afterwards 

 called Sophus Müller's Naze, just where the two north-going parties 

 separated from each other. 



Spiriferina Mylii is very closely related to several of the species 

 that have been described from the Carboniferous and the Permian 

 beds, but, as far as we have been able to discern, it differs distinctly 

 from them, both as regards the form and the sculpture. For example, 

 the difference in form between our species and Sp. nasuta Waagen 

 (1882 — 1884, PI. 49, Figs. 1—2) is somewhat inconsiderable, but our 

 form has more sharply defined ribs and more vaulted valves. 

 Spiriferina Panderi Möller, which Tschernyschew (1902, p. 517, PI. 

 37, Figs. 3—4) considers as also including Waagen's Sp. nasuta, has 

 the tongue-like expansion of the anterior edge of the Л'еп1га1 valve 

 so distinct, that the outline of the shell forms a triangle with inflexed 

 sides. Sp. Welleri Girty (1908, PI. 14, Figs. 17—19), has the form 

 of the shell in fairly close agreement with ours, but both the arch- 

 ing and the sculpture are very different, which latter feature, in the 

 case of the other species before mentioned, also differs considerably 

 from that of Sp. Mylii. 



The writers who have discussed this genus thoroughly have 

 divided it into groups, each possessing some typical species, and for 

 our species we find room in the group which, by Waagen and 

 Tschernyschew is characterized by Sp. insculpta Phill., and by 

 Girty in the section, "lamellosæ" \vhich comprises the groups char- 

 acterized by Sp. Billingsi Shum. and Sp. transversa M'Chesn. The 

 species which the writers in question refer to the groups mentioned 

 differ very considerably from our species as regards the general 

 form, etc. On the other hand, the figuring of the shell-sculpture of 

 Sp. Billingsi, given by Girty (1908, Pl. 14, Fig. 16), is in perfect 

 agreement Avith Sp. Mylii. 



A species which, in many points, agrees with Sp. Mylii is Sp. 

 salemensis Weller (Weller 1914, p. 296, PI. 36, Figs. 1—5) from 

 the Salem limestone in Illinois. This species has a broader shell, 

 and a narrower mesial sinus and median rib than ours, but, other- 

 wise, the profile of the shell and the structure of the cardinal area 

 especially, present a great analogy to that of Sp. Mylii. 



As regards the size of the shell, it should be pointed out that 

 Sp. Mylii is one of the largest species hitherto described. 



