534 Reviews. [July? 



we may say in passing, that we believe even Professor Kolliker 

 under-estimates the extent of its development, for from personal ob- 

 servation we feel satisfied that in many of the larger and more active 

 Infusoria, it foreshadows through a recurring, if not constant, system 

 of accessory canals, the circulating apparatus of the planarian worms 

 and of other animals ranking higher in the scale. The feature, how- 

 ever, in the Infusoria which has wrought the most important change 

 in their zoological value is the reproductive apparatus, for it is 

 clearly shown in accordance with the researches of Dr. Balbiani that 

 they are provided with the essential elements which distinguish the 

 sexes, and that they follow, in this respect, the great developmental 

 law prevailing throughout the animal realm. 



When it is remembered that the forms here treated of vary from 

 roth down to 'roooth of an inch in length, it must be conceded that 

 they are highly organized, and it may be added also that they possess 

 active locomotive powers, and that although no trace of a nervous sys- 

 tem has yet been discovered, it is highly probable that they have the 

 capacity of selecting food, and (according to many observers, including 

 the author) are endowed with a will, however limited in this instance 

 may be the acceptation of the term. 



Below the Infusoria Professor Kolliker places one other group of 

 animalcula), namely, the Gregarinidce, microscopical parasites often 

 found in the lower types of aquatic worms, and Entomostraca, which are 

 still more obscure in their structure and development than the Infu- 

 soria ; and next in order above the last named are what he terms the 

 R/rizopoda proper, including the well-known Actinophrys sol, the Glo- 

 bigerince, and Foraminifera. The last two are the best known of the 

 Protozoa in England, for they have been made the subjects of special 

 study by our English microscopists, and the chief authorities are Dr. 

 Carpenter, Professor Williamson, G. C. Wallich,* H. J. Carter, and 

 Dr. Strethill Wright. 



Little is, however, known of the physiological nature of this group, 

 their beautiful many-chambered shells being their chief attraction, 

 and we are induced to pass them by for the purpose of introducing 

 our readers to the one placed next above them by the author, namely, 

 the Radiolarice, which have not yet, as far as we know, been systema- 

 tically described in the English language, and are but little known 

 even to the initiated in Microscopical Science. Indeed, it is only 

 necessary to state that although the author of the work before us 

 describes with great minuteness thirteen distinct genera and several 

 species, there is no mention of any one of them, nor of the group 

 itself, in the second edition of the ' Micrographic Dictionary,' in order 

 to show that they are all recently discovered types. 



And what exquisite forms do these Radiolarise exhibit ! We feel 

 sure that their beautiful shapes have only to be seen by our microsco- 

 pists, to make them forget Diatoms and Desmidias in their anxiety 

 to possess them ; for, along with the beautiful cases of these they com- 



* See his paper No. I. ' Quarterly Journal of Science,' and Figs. I-C in the 

 Plate appended to the paper. 



