44 CANADIAN FOSSILS. 



South Sea Islands, shew a great resemblance to our fossils, which 

 on closer study becomes more striking ; and I am induced, notwith- 

 standing slight differences of structure, to regard Recept acuities as 

 belonging to the same family, and as having a greater resemblance 

 to the complex than to the more simple forms of the Orbitolitidae. 



It will be desirable first to shew what is the structure of Orbito- 

 lites, as given by Dr. Carpenter in his memoir, "Trans. Phil. Soc," 

 volume for 185G. If the enlarged figure with vertical and horizontal 

 sections in his plate 5, fig. 6, be taken, as he intends them, to shew 

 the general structure of a compound Orbitolite, it will be seen that 

 the greater part of a vertical section through a disk is occupied by 

 the simple columnar cells which form the basis of the whole struc- 

 ture, and which are produced in successive rings around the globular 

 central chamber. The cells of one ring alternate with those of 

 the next, and form, when the superficial layer is removed, or as seen 

 in horizontal section, a quincunx arrangement of circular cavities. 

 Each ring of cells is connected with the next by small perforations 

 giving passage to the minute stolons of sarcode, and of these there 

 is only one to each cell in the simple forms, but they are numerous 

 in the more complex varieties. Besides these small connecting stolons 

 which link together the cells of one circle with those of the next, 

 there are others, concentric ones of large size, which connect the 

 cells laterally, there being in the complex form an upper and a lower 

 great concentric stolon running along the top and the bottom of all 

 the columns. It is from these stolons that the superficial segments 

 take their rise, and not directly from the crown of the large cell itself. 

 In the simpler type there is no distinction into superficial and median 

 cells, nor any great concentric stolons above or below, the connect- 

 ing pores being placed about the middle of the large cells, which 

 are often bent in shape. (See figures 4, 5, 7, in plate 5 of Dr. Car- 

 penter's paper.) 



In the Orbitolites of the Paris basin there is not that clear separa- 

 tion of the superficial from the columnar cells which exists in the 

 other form ; — the upper or outer cells being in fact the upward or 

 downward continuation of the columns themselves, and only sepa- 

 rated from them by the large stolons before described. (See his 

 plate 6, figs. 10, 11.) 



Receptaculites. — In the possession of great columnar cells, with 

 large connecting stolons above and below, and with several smaller 

 ones on the sides of the columnar cells, our fossil agrees with the 

 complex forms described by Dr. Carpenter, but (as in the Parisian 



