Bihliographical Xotices. 233 



little digression may be excused. Why should not both 

 Ciliata and Suctoria be treated as classes? Conceded that 

 Btitschli is right in regarding the tentacles as mouths, and I 

 believe so, that would not necessitate ranging them together. 

 Tlie possession of cilia by the Acinetina, in the early stages of 

 development, has possibly been overestimated. How many 

 features are shown in the earlier or larval stages of other and 

 higher animals to disappear at a later period^ e. g. cilia in 

 Mollusca (velum) and Echinodermuta? If an amoeboid stage, 

 or the development and disappearance of flagella, were accorded 

 so much significance, how should we then, with good reasons, 

 regard the Rhizopoda, Sporozoa, and Flagellata as so many 

 classes ? The close resemblance of the phenomena of conju- 

 gation in the Ciliata and Suctoria is certainly significant ; 

 but we have essentially identical ways of fecundation &c. of 

 the ova in different main groups of Metazoa. In their definite 

 formations the Ciliata and Suctoria are as much different from 

 each other, or much more so, than, for example, the classes of 

 vertebrates and arthropods. The question seems to be ratlier 

 one of logic : if tlie Suctoria in their definite stage are to be 

 considered a degenerated type of Ciliata, they must be ranged 

 under the same head as a subgroup ; if not so, they may well 

 rank as a class at the side of the Ciliata. 



New Philadelphia, Ohio, 

 April 1898. 



BIBLIOGRAPHICAL NOTICES. 



A Natural History of the British Lepidoptera. A TexthooTc for 

 Students and Collectors. By J. "W. Tutt, F.E.S. Vol. I. Son- 

 nenschein, January 1899. 8vo, Pp. vi, 560. 



To the superficial mind it might appear that there was already a 

 sufficiency of works on British Butterflies and Moths ; and yet 

 many of those which have recently appeared treat of the subject 

 from an enlarged standpoint, and cannot be denounced as super- 

 fluous. Among these we have met with none, not even Mr. Barrett's, 

 which approaches the work which Mr. Tutt has undertaken, for 

 comprehensiveness and richness of detail. The amount of matter, 

 too, which it contains is enormous, for it is so closely printed, and 

 small type is so freely used, that every page probably contains on an 

 average from two to four times the amount of matter which might 

 reasonably be expected to occupy a page of similar dimensions. 



The first part of the book may be regarded as introductory, and 

 contains chapters on the origin of the Lepidoptera ; the ovum, 

 embryology, and parthenogenesis ; external and internal structure 



