Botany and Zoology. 421 
change of decomposing organic matter in the sealed flasks to living or- 
ganisms, and the question is asked, “ why may not different kinds of ani- 
mals arise from any decomposed sagen ” If the vital i or life- 
art Se 
relations, and classification of animals, and abounds with excellent de- 
scriptions and ea of the structure of species from the various - 
classes, and is a very valuable addition to the few popular American 
works upon the structure of the lower animals. The portions relating 
to Infusoria and the lowest forms of other groups are particularly valu- 
able. Most of the — —. —T in this, as in other parts 
pa beltives that the Protozoa constitute a eas division, as distinct from 
the others as those are among themselves, but he regards them as merg- 
ing gradually into each other, as clouds that touch and mingle somewhat 
at their borders. The bipolar relations in the organization of all ani- 
, Sale and the bilaterality which is equally a fundamental ce of all, 
are well brought a and illustrated, and it is shown that is as char- 
acteristic of Radiata as of the higher groups, and it is cla ie beyond 
Sanidne nstly, that the more or less radiated appearance is subordinate to 
ilate 
Two chapters are devoted to an examination of various forms of the 
lower ciliated Infusoria, and to comparisons between them and low vege- 
table forms, ciliated plant-spores, &c. The Volvor is not neglected in this 
connection, and is left, as it were, suspended between the animal es 
dom on one side and the vegetable kingdom on the other. Several n 
forms are described and se and much valuable snfonvastion added 
to our knowledge of these beings. 
chapter is devoted to the structural features and characteristics of 
ach there is much “see e and in- 
dium and Cereus, Caudina and Asteracanthion among Radi ata; Pectina- 
tella, Fredricella, Ostrea, Helix and ei of Mollusca; is in each case 
illustrated by original figures and descriptions. The excellent figure 
(117) given as Psolus phantapus seems to us to represent rather Cuvie- 
ria squamata D. & K. as we have observed it when fully expanded in 
its native haunts. Possibly an error in the identification of the species 
has ages here, but for ‘the author’s purpose either form would serve 
equally well 
The eharacteristic feature of Protozoa is stated to be spirality or ob- 
liquity, superimposed upon bilaterality. It would seem, however, to be 
