Umbe.] CANADIAN PALEOZOIC CORALS. 73 



In Dr. Bell's Lake Temiscaming specimen (Plate IV., fig. 5) the coral- 

 lites have an average diameter of 1 -5 mm., and are hexagonal or pent- 

 agonal in section ; the interspaces are roughly triangular, about *5 mm. 

 across and occur at the sides of the hexagonal corallites one to each side. 

 The septa are only obscurely indicated. The tubules found in H. catenu- 

 laria between the corallites are present here also ; they are about 4rd 

 the width of the corallites in diameter, and are seen in longitudinal sec- 

 tions to have tabulae ; they are difficult to recognize in transverse sections. 

 Flat or concave and occasionally convex close-set tabulae, about fourteen 

 in a space of 5 mm., are present in the corallites and the tubules have 

 evenly rounded convex or arched tabulae, about fifteen to twenty in a 

 space of 5 mm. (Plate IV, fig. 5a). 



The second specimen from Lake Temiscaming, (Plate I V., fig. 6) collected 

 by Dr. Bell, might almost be regarded as a connecting link between 

 specimens of H. catenularia, L., in which the meshes are very small, and 

 the typical form of H. compacta. In this specimen the spaces between 

 the corallites are generally about the same size or slightly smaller, but 

 occasionally larger than the corallites, and are rather quadrangular in 

 shape ; in other respects this fossil is identical with the above mentioned 

 specimen. In parts, however, of the same specimen the corallites are seen 

 to be in contact and to have the subtriangular interspaces as in Romin- 

 ger's type. The average diameter of the corallites is 1 *5 mm. 



The specimens brought by Mr. Barlow from Lake Temiscaming differ 

 in the following respects from the first mentioned form, viz., the corallites 

 are smaller, circular instead of being hexagonal in shape, and the inter- 

 spaces instead of being triangular are roughly oval or circular and 

 reduced in size : generally six are seen surrounding a single corallite. 

 Longitudinal sections reveal the presence of tubules, from J to J the 

 width of the corallites, with close set, narrowly arched tabulae, about 

 twenty of which are found in a space of 5 mm. The tabulae of the 

 corallites are flat or concave and there are from fourteen to eighteen in 

 5 mm. In some of the specimens the spiniform septa, twelve in number, 

 are beautifully preserved (Plate IV., figs. 8, 8a). The corallites in this 

 form are further apart on account of their walls being proportionately 

 thicker and it is difficult to discern the difference between the tubules 

 proper and what now represent the interspaces greatly reduced in size. 

 In fact, Mr. Barlow's specimens might readily at first sight be mistaken 

 for a form of Heliolites with very few " small corallites" between the larger 

 ones. 



Prof. Coleman's fossil (Plate IV., fig. 7) agrees in the arrangement of 

 the corallites and interspaces with Rominger's figure and Dr. Bell's first 



