222 SOME NEW BOOKS [SEPTEMBER 
in placing the point of origin far back, in Silurian or Devonian times, so that 
there is a certain fitness in the closing speech, that of Mr. Sedgwick, in which 
‘“‘pre-Cambrian times” are suggested as the period of origin, not of mammals 
only, but of all the “great classes of the animal kingdom.” Mr. Sedgwick 
suggests that “the main part of the evolution of organisms must have taken 
place under totally different conditions to those now existing, and must remain 
for ever unknown to us.” We duly altered our belief in Recapitulation to meet 
Mr. Sedewick’s criticisms, and have learnt to hold the cell-doctrine lightly at his 
bidding, but this new iustance of ‘“ thitige Skepsis” makes so heavy a demand 
upon our credulity that we prefer to regard it as a delicate piece of sarcasm. 
Among other interesting papers is one by Messrs. Mesnil and Caullery on 
polymorphism, and the occurrence of epitokous forms in the common littoral 
annelid Dodecacaria concharum. They find that the common form (Form A) is 
viviparous, and apparently reproduces parthenogenetically ; males at least have 
not been found, and reproduction takes place at a time when the males of the 
other forms are not yet ripe. The second form (Form B) is rare, and occurs in 
both atokous and epitokous forms. The modifications of form displayed are in 
all respects similar to those displayed by the Nereids and Syllids. The epitokous 
forms leave their tubes and become free-swimming. Very rarely a third form 
was found (Form C), which likewise becomes epitokous, but the changes are 
less marked than in B. Of this form females only were found. The authors 
are uncertain whether these forms are to be regarded as allied species or as 
constituting a polymorphic species. The point of special interest is that the 
phenomenon of epitoky has not previously been described in sedentary 
Polychaetes. It seems probable that it occurs much more frequently among 
Polychaetes than is at present suspected. 
The volume is furnished with a bulky appendix, a considerable portion of 
which is taken up by ‘Correspondence on the Nomenclature of Lepidoptera,” 
being the classified answers to questions circulated among certain entomologists 
by Sir George Hampson. Whether this will advance the science of entomology 
or not, we cannot undertake to say, but it can be confidently recommended 
alike to the psychologist and the student of human nature. If, as we are led 
to believe, systematic or other work is almost impossible to the entomologists, 
on account of the difficulties of nomenclature, there seems no reason why they 
should not occupy their time instead in classifying the views of their fellow- 
workers on various subjects, but the result seems slightly ludicrous to the 
onlooker. 
The appendix also contains in full Prof. Hubrecht’s paper on the ‘‘ Develop- 
ment of the Placenta in 7Zarsius and Tupaia, with Observations on its 
Importance as a Haemopoietic Organ,” which is fully illustrated by plates. 
The volume contains abstracts of numerous other papers in addition to those 
mentioned, but most of these have been previously published elsewhere. 
N. 
INSECTS. 
Insects (Part II). By Davin SHarp, M.A., M.B., F.R.S. Being Vol. VI. of 
the Cambridge Natural History. Edited by S. F. HARMeEr and A. E. 
SHIPLEY. Pp. xii. + 626 with 293 figures. London: Macmillan, 1899. 
Price, 17s. net. : 
A hearty welcome will be given by all students of insects to this concluding 
portion of Dr. Sharp’s monumental work, the commencement of which appeared 
four years ago in the fifth volume of the ‘Cambridge Natural History.” The 
volume now before us deals with the higher Hymenoptera, the Coleoptera, the 
Lepidoptera, the Diptera, the Thysanoptera, and the Hemiptera. It must be 
admitted that this arrangement of the orders of insects is unsatisfactory ; the 
Lepidoptera, for example, are removed far from their allies the Trichoptera 
