420 JOURNAL OF THE PLYMOUTH INSTITUTION. 
THE DEPTHS OF THE OCEAN. 
SYLLABUS OF LECTURE BY CAPTAIN INSKIP, R.N., F.R.G.S, 
(Read February 3rd, 1881.) 
THE bed of the deep sea until recent years an unknown region. 
Sounding and dredging. Supposed sudden dip in the bed of the 
North Atlantic, off the Irish coast. Porcupine’s expedition in the 
North Atlantic in 1869—first cruise, second cruise, third cruise. 
Porecupine’s expedition southward to Strait of Gibraltar, and up 
the Mediterranean in 1870—first cruise in North Atlantic, second 
cruise in Mediterranean. Notes on the Challenger’s work—lIn the 
Atlantic ; in the Southern Ocean ; from Australia. to China. The 
deepest sounding. In the Pacific. Concluding remarks. 
HABITATION OR ENVIRONMENT? 
A CHAPTER IN THE THEORY OF EVOLUTION. 
SYLLABUS OF LECTURE BY MR. F. H. BALKWILL. 
(Read February 10th, 1881.) 
MeanineG of the word “habitation” contrasted with that of the 
word “environment.” Gradation of life. Correspondence between 
habitation and life. Examples given. The salmon, grizzly bear, 
and camel. Evidence of the nervous system with regard to cor- 
respondence between consciousness and the habitation. Diagram- 
matical representation of an ascending series of habitations. 
Meaning of correct biological classification. Line of descent of 
man. Man defined by the use of language or weapons. Query 
which? Conclusion. 
