190 Dr. Matox's and Air. Rackett's 
celebrated cabinets on the continent, but more especially from 
that of Spengler, whose collection deserves to be considered as 
one of the most extensive, as well as the most replete with rare 
and interesting specimens, that has ever been formed for the study 
of the Testacea. The name of SPENGLER ought to have a 
place also among the writers on these subjects, descriptions of 
several shells from his pen having appeared in different German 
publications; and it has not unmeritedly been attached, as a spe- 
cific denomination, to a Mactra described by Chemnitz. 
The work of which we are here particularly treating does not 
materially differ, as to system, from the Linnean school, but 
(excepting just the definitions of the species and the synonyms) 
is written wholly in the German language; and it is much to be 
lamented that it has not assumed any other dress, for the fulness 
of the descriptive part renders it highly worthy of being consult- 
ed. At the period when the use of the Latin language was thought 
indispensable in books of science, the attainment of knowledge 
was attended with much fewer difficulties than at present, when, 
though the use of a dead language may not be absolutely neces- 
sary, there is certainly as much need as ever of some one tongue 
being made the medium of communication among philosophical 
men of all nations. We do not hesitate to pronounce the volumes 
of Martini and Chemnitz as constituting a Testaceological library 
in themselves ; and we cannot, therefore, adequately express our 
regret at their utility as books of reference being limited to the 
German scholar, when it might, without any considerable diffi- 
culty, have been extended to all lovers of the science by the sub- 
stitution of French. 
Chemnitz was author of several Testaceological papers inserted 
in different foreign journals, but they are not of sufficient im- 
portance to require being particularized. His collection of shells 
is 
