Jan Mayen Mollusca 



t'i'oni 



the Norwegian North Atl. Expedition in 1877. 



By 



Herman Friele. 



Brachiopoda. 



Terrhratula arctica n. s. Fig. 1, a to c. 



Shell oval, like T. minor, rostrum short, foramen complete, 

 though but slightly connected, placed close up to the umbo of 

 the hoemale valve, under which the deltidium is almost hidden. 

 Apophysis frail. Size L. 14 B. 12 m. m. 



This form approaches the T. minor Philippi (affinis Calcara). 

 In outer characteristics tjie deviation is shown by a shorter rost- 

 rum and by the position of the foramen, which in T. arctica is 

 placed so directly above the hoemale valve, that the deltidium is 

 fJmost hidden. Deltidium is moreover narrow and very slightly 

 connected. Compare Fig. l'*. (T. arctica) to Fig. 2. (T. minor Vh.) 



The apophysis of T. arctica is very much weaker and thinner 

 and the crura-processes are placed farther apart than in T. minor» 

 Compare Fig 1^. (T. arctica) to Fig. 2^. (T. minor Ph.). 



Found at Station 237 — ^* 4 miles S W, off Jan Mayen — 

 263 fathoms. The Bottom small and big boulders; the tempera- 

 ture at the bottom -f- 0. 4° C. It appeared numerous, but most 

 of the specimens were broken in the dredge. 



This is the first representative of the genus Tcrchratula pro- 

 per that has been found in the arctic seas. Mr. Th. Davidson 

 informs me that T. minor has been found south of the Cape of 

 Good Hope on the „Challenger Expedition.* 



