and their Anatomical peculiarities. 



331 



The Caudal Fin is attached, as in the salmonidse, to a very fleshy root, 

 being moved by very powerful muscles. It is forked, and consists of 

 thirty-six flattened, articulated, firm, and highly elastic rays. These are 

 separated by a deep cleft into two conical fasciculi, the lower one being 

 deeper, stronger, and more elongated, while each is inserted into the free 

 border of one of the two segments of the semilunar shaped terminal caudal 

 vertebra.* The seven highest rays of the root of the tail arise together 

 from the integuments over the three or four last superior spinous pro- 

 cesses, while the four lowest rays proceed from a line near the apices of 

 the two last inferior spinous processes. t 



The Pectoral Fins in this species are each furnished with ten soft 

 rays. 



The Ventral Fins present each seven soft rays. 



Edinburgh, 4 Surgeons' Square, 

 July 27. 1839. 



* Plate IV. fipr. 1. t Ibid. 



Table of Mean Temperature of Orkney. Communicated by 

 the Rev. Charles Clouston of Sandwick Manse. 



The following Table shews the mean monthly and annual 

 temperature from 1827 till 1838 inclusive, with the mean 

 temperature of these twelve years, which may be considered 

 the mean temperature of Orkney. The register was kept at 

 the manses of Stromness and Sandwick, and marked twice a- 

 day, at 10 o'clock a. m. and 10 p. m. 



