the Cruise of H.M.S. ' Challenger. 3 467 



Juan Fernandez on the evening of the 13th, and remained there two 

 days observing and photographing the scenery, and making such col- 

 lections of animals and plants as it was possible to make in so short a 

 time. We weighed anchor on the evening of the 15th, and stood 

 towards Valparaiso, where we arrived early on the 19th. 



The section from Papeete to Valparaiso (Plate 17) is about 5000 

 miles in length, and is naturally divided into two parts — the run south- 

 wards to the parallel of 40° S., and the course along that parallel towards 

 Valparaiso. In the entire section we established 20 stations bearing 

 numbers from 279 to 298. At each of these the ordinary bathymetrical 

 and temperature observations were taken successfully ; and the trawl or 

 dredge was lowered on thirteen occasions, twelve times successfully ; on 

 one occasion the trawl-line carried away. 



Setting aside Station 279 in 680 fathoms close to Tahiti, the mean 

 depth throughout the section was 2139 fathoms, considerably less than 

 that of the meridional section from Honolulu to Tahiti, and very much 

 less than that of the section in the North Pacific between Japan and 

 San Francisco. The nature of the bottom is very much the same as in 

 the meridional section, red clay imbedding nodules and lumps of various 

 sizes of manganese peroxide, and passing in the shallower soundings into 

 more or less pure Globigerina-oozQ ; and, as in the section between Hawaii 

 and Tahiti, the fauna is generally meagre. The trawling between Juan 

 Fernandez and Valparaiso (Station 298) was particularly interesting ; 

 animal forms were much more abundant than they usually are in the 

 Pacific ; and the general character of the assemblage resembled in a re- 

 markable degree that of the fauna of the Southern Sea in the neighbour- 

 hood of the Crozets and Kerguelen, many of the species, including some 

 singular Urchins of the family Ananchytidae, being identical. The bottom 

 at this station was a bluish mud, the surface layer containing little or no 

 carbonate of lime, and, curiously enough, a deeper layer, with a con- 

 siderable proportion of Globigerina-sheWs. There was no considerable 

 quantity of manganese in the sounding. Notwithstanding the consider- 

 able depth of 2225 fathoms, the conditions in this locality seem much 

 more favourable to animal life than even the manganese area ; and I am 

 inclined to think that we had struck upon one of the highways by which 

 migration takes place to the northward from the Southern Sea. The 

 following Table (p. 468) gives the proportion in which the principal animal 

 groups are represented in the trawlings in this section. 



From Tahiti to Station 288, in lat. 40° S., the upper temperatures 

 fell regularly and steadily ; but the isothermobaths below 80° C. showed 

 rather a tendency to sink, indicating a somewhat thicker layer of water 

 at a temperature above 3° C. towards the southward. The cause of this 

 apparent anomaly will be discussed hereafter. From Station 289 the 

 isothermobaths run on to Valparaiso with scarcely an oscillation of any 

 importance (Plate 18). 



