14 OLAF HOLTEDAHL. [SEC. ARCT. EXP. FRAM 



tubes in the Arctic form. Similar cells are also known from the genera 

 Pleurodictyum and Lyopora. In all the three genera mentioned these 

 tubes are relatively much smaller than in ours, and the wall shows 

 no curvature round them. The tubes remind one also to some extent 

 of the "spiniform corallites" of many Monticuliporidae. 



As to the other characters of our form septal spines are found in 

 most of the polygonal cells. The greatest number seen in one cell in 

 tangential section is 45 while their length does not generally amount 

 to more than y 5 V of the diameter of the cell. Very often spines in 

 neighbouring cells are seen to be directly opposed to each other, having 

 their base at the same spot. 



The pores of the new form are much the same as in Favosites, 

 Compared with that genus they are relatively large, the diameter vary- 

 ing from 0,150,25 mm. or from more than Va to Vs f tne width of 

 the walls that they perforate. In one place only (see pi. V, fig. 3) I have 

 seen several of them together and they appear somewhat irregularly 

 arranged. 



With its prominent, cylindrical or subcylindrical longitudinal tubes, 

 without tabulae, the form here described differs essentially from any 

 one known to me and I propose for this and similar, in other respects 

 Favosites-like forms the generic name Parallelopora. 



Occurrence: B, upper part, over the fragment-limestone, Valley 

 south of Borgen. 



Cladopora HALL. 

 Cladopora rectilineata SIMPSON. 



PI. IV, fig. 7. 

 1889. Cladopora rectilineata SIMPSON. Trans. Amer. Philos. Society. 



New Ser. vol. 16, p. 459, fig. 30. 

 1903. Cladopora rectilineata WELLER. Paleontology of New Jersey. 



Vol. 3, p. 221, pi. 17, figs. 14-17. 



1913. Cladopora rectilineata SWARTZ. Geol. Survey of Maryland. Lower 

 Devonian, p. 216, pi. 25, figs. 47. 



Several pieces of a dark limestone showing a great number of the thin 

 stems of this species, in places very nicely weathered out. They have 

 a diameter of from 2 to 1.5 mm., with the apertures of the cells arranged 

 in about ten rows. Some of the stems shown on pi. IV, fig. 7 are too 

 much worn, and the arrangement of the interior tubes appears here 

 less linear than is the case when the real apertures are seen on the 

 original surface. 



