Reviews^-J. F. Whiteaves on OrtJioceratidce. 373 



of the shell is viewed edgewise the rounded ends of the protocouch 

 may be seen slightly projecting on either side. 



The suture line of the first septum is marked by a prominent 

 narrow saddle over the siphuncle, as in the Angustisellati of Branoo. 

 According to Mr. Brown's observations, " the total number of main 

 lobes and saddles of the adult shell is apparently developed at the 

 second septum." 



The shape of the septa gradually changes from the lunate form 

 of the first septum "into a more and more circular form, until it 

 becomes completely circular in the straight portion of the shell," 

 and in the straight portion, which " begins somewhere between the 

 twentieth and twenty-fifth septa," the form of cross section "passes 

 gradually from a circular to an ovoidal, laterally-compressed form, 

 and finally in the adult into a somewhat triangular form." 



"The outer nacreous shell when preserved is found to be marked 

 by minute tuberculations of irregular shape ; these in turn give place 

 to the parallel curved lines seen in the adult shell. These parallel 

 lines first appear about the fourteenth septum, and they soon 

 completely obscure the tuberculation. Between the first and second 

 sutures there is apparently an interruption in the growth of the 

 shell, appearing as a line resembling a suture line. This line seems 

 to be slightly raised above the general shell substance; it extends 

 over the end of the ventral lobe of the second suture and back in 

 a simple curve to near the lateral ends of the first suture. In 

 breaking away the nacreous shell substance to follow the sutures, 

 the break nearly always follows this line, leaving the protoconch 

 covered by the original shell. Over the area thus left of the original 

 shell substance the tuberculations are found to be more circular in 

 outline and closer together than in the succeeding portions of the 

 shell. It is believed that the portion of the shell thus bounded 

 represents the original embryonic chamber, or protocouch, which 

 would thus extend beyond the point where the first septum was 

 subsequently developed. A section in the plane of the spiral, but 

 not quite median, showed the shell to be composed of successively'^ 

 deposited layers, and the first of these was seen to extend a short 

 distance beyond the first septum, thus tending to confirm the above 

 belief." An examination of the young of ScapJiites Conradi, Morton, 

 showed that in this shell also the outer limit of the protoconch was 

 between the first and second septa. 



Mr. Brown states that after considerable investigation he is not 

 able as yet to trace the phylogeny of the species. G. C. C 



IV. — The Orthoceratid^ of the Trenton Limestone of the 

 Winnipeg Basin. By J. F. Whiteaves. Transactions of the 

 Eoyal Society of Canada, Vol. IX. 1891, pp. 77-90, Pis. V.-XI. 



THE species here described were, with one exception (from the 

 Nelson River, in Keewatin), obtained in the province ot 

 Manitoba, "either from the valley of the Red River (at Lower Fort 

 Garry or East Selkirk), the western shore of Lake Winnipeg, or 

 from some of the numerous islands in that lake." " The term 



