158 Miscellaneous Intelligence. 
those lines in which a magnetic een: freely ple tbe places its 
length. I did the same with the earth b tting across those 
lines which are pean out by the poitting of ial dipping-needle. 
Therefore, what am I authorized to infer? When the effects are 
the same, ‘the secinaed must be the same; for according to all the 
principles of philosophy, and conformably to that universal ex- 
perience which we call common sense, like causes produce like 
Sec ose who are desirous of possessing in a compressed form 
the iain facts “a terrestrial magnetism, we strongly recommend 
Zodlogy. No. VIL. Jevision of the Echini ; by ALEX 
Agassiz. Parts I and II, with 49 plates. Cambridge, Mast 
important one yet published upon the Echini. Part I contains a 
very complete bibliography; a chapter on nomenclature; a 
se ln list of all the genera and species hitherto named, 
each n: when it first 55 ee being printed in black- faced type ; 
aa alphabets! list Sree e genera and species, with their full 
synonymy, and a ae the authenticated Pokies of each; a 
‘y ged; 
the geouraphisal distribution, including a list of all the known 
species with their geographical range, and special lists of the 
i nd faune. 
littoral species found in the various districts a The 
geographical haat is illustrated by seven plates, rinted in 
colors, m bir the division of the oceans into lit- 
quent writer, has been adhered to, and will be of great conven 
ience to those who have occasion to study the synonymy. 
In the investigation of the synonymy, Mr. Agassiz has had unusual 
facilities for the examination of ori inal and authentic specimens, 
for besides the unrivaled collections of the Museum of Compara- 
tive Zodlogy, he has had excellent opportunities to study all the 
principal collections of Europe, and has thus examined the be 
specimens, even of many of the earliest writers on In 
this, the most laborious part of his work, he has evidently pen 
ibe to make the synonymy as accurate and complete as pos 
sible. 
The ous perplexing questions that invariably arise in a 
suveliie tahe early synonymy, especially of genera, have bee 
treated very —— and t ee others may not agree with 
the author as to the names to be adopted in special cases, he has 
presented all the data that is needed to decide the questions, let 
the principles of nomenclature that we adopt be what they ma 
The point that will be most opposed is, perhaps, the restora 
