406 REVIEWS AND BOOK NOTICES. 
that in the most complicated pedicellarize known, with a freely 
movable stalk and with snapping jaws, we have only a very grad- 
ual modification of the simplest sort of limestone network found . 
in all Echinoderms in the earliest stages of the embryonic devel- 
opment, while still in the Pluteus-stage, and that we have an 
unbroken sequence from this primitive network to form, on the 
one side the most diversified spines, and on the other equally 
variable pedicellariz, and that we must consider the latter in their 
most complicated forms as nothing but highly specialized spines. 
REVIEWS AND BOOK NOTICES. 
Tue DEPTHS OF THE Sea.* — One could not but form a favora- 
ble impression of this sumptuously printed book from its attractive 
exterior; the pleasant impression is deepened by a perusal of it. 
The narrative is on the whole clear and graceful: the novelty of 
the facts and the fine illustrations will interest the lay reader, and 
the scientist will find placed before him in an accessible form the 
results obtained by the British explorations by means of the 
dredge and thermometer in the depths of the eastern north At- 
lantic and the Mediterranean Sea. 
The marine zoologist will be led after reading it, as perhaps not 
before, to study more carefully the temperature and chemistry of 
the water in which he dredges, while the broader questions of the 
geological and geographical distribution of animals will engage 
his attention perhaps the more after reading Prof. Thompson’s 
interesting summary of the joint work done by Carpenter, the 
physiologist and physicist ; Jeffreys, the conchologist ; and Wyville 
hompson, the accomplished zoologist. After the introduction, we 
have chapters giving an account of the cruise of the “Lightning,” 
those of the ‘Porcupine ;” chapters on deep-sea sounding, and 
deep-sea dredging, on deep-sea temperatures, the Gulf Stream, the 
deep-sea fauna, and the continuity of the chalk. 
In the introduction (p. 44) the idea is presented that deep-sea 
* The Depths of the Sea. An Account of the general gre of hs Dredging Cruises 
of H. M. S.S. “ Porcupine” and “ Lightning” durin = he summers of 1868, 1869, and 
1870, scientific direction of Dr. Carpenter, J. Gwyn reesei opie Dr. Wyville 
Thompson. By C. Wyville Thompson. With numerous illustrations and maps. New 
York and London, » Mac millan & Co., 1873. 8vo. pp.527. (The illustrations are in 
Macmillan, he pul lish ) 
