586 Karl A. Grönwall. 



Jakowlew (1912, PI. 4, Fig. 8), mentions this species from the 

 Permo-Carboniferous (Arta stage) in the Donetz basin. 



For the group of Productus of which Pr. punctatus is the type, 

 Stuart Weller (1914, p. 138) has proposed the establishment of a 

 new genus, under tlie name of Echinoconchus, and Thomas the 

 genus Pustula. 



N:o 25. Productus pseudohorridus Wiman. 



PI. XXIX, Figs. 6—10. 



Wiman, p. 74, PI. 17, Figs. 1—11. 



Of this typical species there are 3 unquestionable specimens : 

 one full grown, showing both the ventral and the dorsal valve (the 

 figured), found in a boulder at the Eskimo Naze (N:o 213); a 

 fairly full-grown specimen of a ventral valve found at the same 

 place {N:o 197), while a young specimen was found on the mainland 

 behind Henrik Kröyer's Islets {N:o 21^ d). All these occur in the 

 same rock, a light-grey, fine-grained, somewhat sandy limestone. 

 There is, in addition, a ventral valve {N.o 214 c) from the mainland 

 at Henrik Kröyer's Islets, which however, is not so well preserved 

 as to allow of fully positive identification. 



These specimens agree so closely with Wiman's description that 

 only unimportant additions need to be made. Specially deserving of 

 attention is that Fig. 9 shows the correctness of Wiman's supposi- 

 tion thai, in the case of fully complete specimens, the greatest width 

 lies somewhat in advance of the ears. The cast of the dorsal valve 

 shows how deep this is, and the form of the mesial fold, which 

 corresponds to the sinus of the ventral valve, as well as the even 

 curving of the anterior part of the dorsal valve towards the margin 

 without any geniculatioii at the limit of the visceral room. 



In Spitzbergen, this species occurs in the Spirifer limestone and 

 in the Productus flint. 



N:o 26. Productus timanicus Stuckenberg. 

 PI. XXIX, Figs. 11—16. 



Stuckenberg, 1875, p. 86, PI. 1, Figs. 1—7. 



TscHERNYscHKW, 1902, pp. 306, 638, PI. 30, Fig. 5; PI. 57, Figs. 



1-6. 



Stuckenberg, 1905, p. 65, PI. 6, Fig. 10. 



Wiman, 1914, p. 75, PI. 17, Figs. 19—21; PI. 18, Figs. 1-6. 



This species is one of the fossils that occur most numerously 

 in our collection, and is represented both by fairly young specimens 

 and by fully grown ones, a fact which, at first, rendered identifica- 

 tion difficult. 



