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POPULAR SCIENCE REVIEW. 
small quantity of manganese. It would be interesting to know 
whether this is connected with the extreme depth. Professor 
Wyville Thomson thinks not. The depth at Station 5 was 
2,700 fathoms, and on that occasion foraminifera were 
abundant, and several bivalve molluscs were captured living. 
The difference in depth cannot be so effective as to arrest the 
life of organisms to the secretion of whose testes the grey 
Atlantic ooze is due. He is inclined to attribute this deposit 
to a movement of the water from some special locality — 
possibly the mouths of the great South American rivers. 
On Sunday, March 2, the first patches of Grulf-weed were seen. 
On the morning of the 4th a fine decapod crustacean was caught, 
having the characters of Astacidce , but differing in the absence 
of eyes and eye-stalks.* The absence of eyes, remarks Professor 
Wyville Thomson, in many deep-sea animals, and their full 
development in others, is very remarkable. f 
A singular absence of higher forms of life has been noticed 
for some days past. “ Not a bird was to be seen, from morning 
to night.” More latterly sharks and dolphins have been seen, 
the latter in pursuit of flying-fish. They are easily deceived by 
a rude imitation of one of their prey, such as a white spinning 
bait, when the ship is going rapidly through the water. On the 
11th the dredge-line was paid out to more than 4,000 fathoms, 
* Vide Dr. Sulim’s paper “ On some Atlantic Crustacea from the Challenger 
Expedition,” PI. XIII., fig. 1. Willemoesia leptodactyla is its right name, the 
generic name Deidamia , under which it is figured in “ Nature,” vol. viii. 
p. 51, fig. 2, being already the property of a North American genus of Sphin- 
gidce. u The eyes are entirely wanting , nor is there, as in Astacus Zaleucus, any 
place left open where you might expect them.” .... “ It is very astonishing 
indeed that, among all crustaceans known to us, Willemoesia approaches most 
closely to the fossil Eryontidce” 
t For instance, a stalk-eyed crustacean from 700 fathoms in which the 
eyes are well developed in shallow water — e.g. JEthusa gramdata — may have 
eye-stalks gradually modified into immovable pointed organs, devoid of 
special sense, while Munida from a like depth has unusually developed 
and sensitive eyes. “It is possible that in certain cases as the sun’s light 
diminishes the powers of vision become more acute, while at length the eye 
becomes susceptible of the stimulus of the faintest light of phosphorescence.’’ 
Absence of eyes is not unknown among the Astacidce. A. pellucidus from the 
Mammoth Cave, in Kentucky, is blind, and from the same cause, but mor- 
phologically, the eyes are not wanting, being represented by rudiments, 
while in Willemoesia there is no trace of them or their peduncles. Mr. 
Wood Mason describes (“ Nature,” June 5, 1873, p. Ill) a macrovrous 
crustacean, a type of a new genus — Nephrops Stewarti — dredged from 250 to 
300 fathoms off the east coast of the Andaman Islands, which had lost its 
organs of vision by disease, but in compensation the anterior and auditory 
organs were greatly developed. It burrows in mud at the bottom. 
