JOHAN KLR. 



[SEC. ARCT. EXP. FRAM 



In the case of />'. canadensis the measurements are partly deter- 

 mined from examples from Scannienac Bay, partly from TRAQUAIR'S 

 reconstruction, and in the case of B. hydrophila from TRAQUAIR'S l 

 excellent illustrations and reconstruction. 



Length of unt. 

 Length of ventr. later, 



proximal part plate from post, 

 of arm. marg. to inner 



cross rib. 



Proportion 

 Figure. 



1. Form from Galgeodden, Elles- 



niere Land 11) mm. 33 mm. 



2. B. canadensis WHIT. Specimen 



from Scaumenac Bay .... 42 58 



3. B- canadensis W mr. TUAQCAIR'S 



reconstruction 25 31 



4. B. hydrophila Ac. THAQI AIR'S 



reconstruction 1718 3132 



1 : 1.74 

 1:1.38 

 1 : 1.24 



1: 1.8 

 1 : 1.77 



As will he seen, the form described differs very considerably from 

 B. canadensis WHIT, but agrees almost entirely with B. hydrophila AG. 

 which is known in excellent specimens from Dura Den in Fifeshire, 

 Scotland in the Upper ( )ld Red Sandstone. 



Since also according to TRAUUAIR'S description the sculpture, the 

 short and broad form of the anterior body plates, and the size on the 

 whole agree in the two forms, I may presume that the remains from 

 Ellesmere Land are either identical or nearly related to B. hydrophila 

 AG. T have not been able to discover any American form showing closer 

 agreement. The most nearly related appears to be B. canadensis WHIT 

 which, however, has considerably shorter arms. 



It is difficult to determine exactly whether the fragments with coarser 

 sculpture also belong to B. hydrophila AG. The variations of sculpture 

 and dimensions in the case of B. canadensis WHIT, show that these 

 fragments may possibly belong to the same form as the others. One 

 fragment, however, shows so coarse and so markedly nodose ribs, that 

 it can scarcely belong to the same species. 



Horizon. From the dark schists of Galgeodden, with remains of 

 plants. -- and from the fish hori/on of Skrap Valley. 



1 R. H. THAOUAIH. The Asterolepidee. Monogr. Pal. Soc. 1894 and 1904. 



