COASTS VISITED BY THE ARCTIC EXPEDITION. 583 



thick and very closely arranged, which, on weathering, gives a very 

 rugose appearance to the corallites ; reticulations between the chain- 

 like pattern on the upper surface of the corallum very small and 

 polygonal ; calices either elliptical or polygonal ; and frequently only 

 two or three corallites occur in the space or vertical wall constituting 

 the reticulations. 



The habit of this variety differs so much from that of the com- 

 mon form of H. catenulatus, or the more ramifying and taller-growing 

 variety, that I am justified in giving it the varietal name. As an 

 extreme variety it deserves recognition and description ; I therefore 

 name it after the indefatigable naturalist to the Expedition. Dana 

 notices Hall's species H. gracilis from the Hudson-river group, 

 Green Bay, Wisconsin, from a lower horizon than Captain Feilden's 

 specimen. H. catenulatus, var. Feildeni, differs from the true H. 

 catenulatus, Linn., from Cape Erazer and Dobbin Bay, by the ex- 

 treme smallness of the reticulations, very closely arranged tabulse, 

 and compact habit of growth. H. escharoides (De Blainv.) is its 

 nearest ally. 



Loc. Cape Hilgard, lat. 79° 41'. 



Halysites catenttlatus, var. Harti, Eth. (PL XXVIII. fig. 2.) 



This form differs considerably from the usual habit of Halysites 

 catenulatus, the chain-like rows of corallites constituting the coral- 

 lum being very much more extended or enclosing larger interspaces 

 or areas, and closely resembling the variety Oatenipora labyrinthica of 

 Goldfuss. The epitheca, too, and the walls are more coarsely rugose, 

 the striae being coarser than in H. catenulatus proper ; this does not 

 appear to be due to age only ; the character is well shown in Gold- 

 fuss's figure (Petr. Germ. p. 75, t. 25. f. 5). Further the series of 

 corallites in the winding loops are much more numerous than in the 

 recognized forms of H. catenulatus. The whole corallum is also more 

 robust in habit, and must have been of large dimensions vertically 

 and laterally. I figure this amongst other variable species in the 

 collection, as being a very aberrant form of Halysites. 



Loc. Cape Erazer, lat. 79° 45'. 



Genus Syringopora, Goldfuss, 1826. 



Syringopora parallela, Eth. (PL XXVI. fig. 1.) 



We have only one specimen of this genus ; it much resembles S. 

 geniculata, Phill., from our Carboniferous rocks. The corallites are 

 cylindrical, tall, slender, nearly parallel, and closely arranged ; the 

 walls are covered by a thick epitheca ; the horizontal connecting tubes 

 rather numerous or closely set, although certainly not so much so as 

 in 8. geniculata ; neither is it our Silurian species S. bifurcata, Lonsd., 

 being more delicate in habit ; and the corallites are more densely 

 packed and more regularly parallel in their upward growth than in S. 

 reticulata, although it much resembles that species. Weathered speci- 

 mens show the infundibuliform tabulse. Little geniculation takes 



