312 Additional Observations on the 



different distances, which they frequently do in most of the 

 true pines. The number of discs in a row, too, is extremely va- 

 rious. Sometimes there are not more than one, two, three, or 

 four, and sometimes there are as many as sixty, seventy, or even 

 eighty, but in general they are not nearly so numerous. 



The second figure in Plate V. represents a portion of a longi- 

 tudinal section parallel to a radius of the Araucaria excelsa. 

 In the upper part there are both double and triple rows of 

 discs, and in parts of the figure there are no discs, a circum- 

 stance which occurs in every species of the coniferae. The under 

 part of the figure represents one of the most elegant groups of 

 discs in double rows that I have ever yet observed. It occurs 

 in the same^ section from which the upper part was taken, but 

 at a little distance from it, and this is the reason why the figure 

 is separated into two distinct portions. The figure is magnified 

 in the same degree as those in Plates II, III, and IV, in the 

 last number of the Journal, namely, about four hundred times. 

 There was not room in the plate for a concentric longitudinal 

 section ; and indeed had it been introduced, it would have shewn 

 nothing different from the one formerly given of the Araucaria 

 from Moreton Bay. 



The Dammara australis, however it may differ in its botanical 

 characters, resembles so closely in the internal structure of its wood 

 the Araucaria excelsa, that the one cannot be distinguished from 

 the other. Both have regular annual or periodical layers, and 

 in both the layers are similarly terminated. I'he form of the 

 meshes are also similar. The discs or areolae in the longitudinal 



o 



section parallel to the radius, are similar in size, form, and 

 arrangement, and in the longitudinal concentric section, the ex- 

 pansions in the partitions are equally similar. 



It is worthy of remark, however, that the cohesion of the ra- 

 dial partitions in the transverse section of both these species, is 

 much greater than in the Araucaria from Moreton Bay ; and 

 that in this respect the Dammara is somewhat superior to the 

 Araucaria excelsa. 



The species of Callitris I have now to notice, is a new one 

 from Morten Bay, and is known in New Holland by the name 

 Moreton Bay cedar. It shows no indication of regular annual 

 layers, but there are indications of the process of vegetation 



