1878.] 'lightning' and 'porcupine' expeditions. 



Second Cruise. 

 Mediterranean. 



397 



1 



Very few productive deep-sea dredgings were made during this 

 second cruise. 



Some of the new and peculiar species of Mollusca, which were 

 procured in these expeditions, have been already described and 

 noticed by me in the fifth volume of * British Conchology,' the 

 ' Proceedings of the Royal Society,' and the ' Annals and Magazine 

 of Natural History.' I will now endeavour to complete the work, 

 and to record all the species, with particulars of their geographical, 

 bathymetrical, and geological distribution. Figures of the more 

 remarkable species will also be given. 



I commence with the class usually regarded as lowest in the scale 

 of organization, or the least-specialized, among the Mollusca, viz. 

 the 



BRACHIOPODA. 



Notwithstanding the long and persevering labours of that monarch 

 of Brachiopodists, Mr. DavidsoD, as well as of Professor King, Mr. 

 Dall, and other excellent zoologists, the natural arrangement and 

 coordination of this difficult class cannot be said to be yet satisfac- 

 torily established. I prefer to steer a middle course between extreme 

 systematists, and not to follow Professor King in making Terebratula 

 cranium the type of another genus (his Macandrevia), nor to com- 

 press all the family of Terebratulidte into the single genus Terebra- 



