122 MR. W. K, PARKER ON THE STRUCTURE AND 
For although, of necessity, none of these lie directly below the Mammal, yet they 
are of great profit to the student of Mammalian descent, when the mask of their own 
particular specialisation has been removed, and that which is essential to the Verte- 
brate is seen in each “ platform,” lower and still lower, so as to help the mind to form 
some useful, if inadequate, idea of the lost types that did underlie, and indeed give 
rise to, the existing Mammalia. 
The Common Hedgehog, besides being more easily obtained than most kinds, is, 
I feel certain, one of the most generalised types in the Order: it has escaped further 
from the Metatherian border than some (e.g., Lhynchocyon), that nevertheless show 
much greater signs of advance towards the higher Eutheria. Thus the various 
characters seen in Hrinaceus are none of them so low as some to be seen in the type 
just mentioned, whilst none are so high as others. On the whole I look upon this 
genus as most normal, for the Order itself, as well as a good instance of a low Eutherian 
type, with which to compare any of the higher and more specialised kinds—a sort of 
useful supra-marsupial norma,* 
BIBLIOGRAPHICAL LIST. 
ALLMAN, Professor George J., F.R.S. “On Potamogale.” Trans. Zool. Soe., vol. vi., 
1869 ; plates 1, 2. 
Aston, G.R. ‘On an undescribed Shrew from Central America.” Proc. Zool. Soc., 
1877, pp. 445, 446. 
Anperson, John, M.D. ‘On the Osteology and Dentition of Hylomys.” Trans. 
Zool. Soc., VIIL, Art. XTII., pp. 453-467 ; plate 64; 1874. 
Austen, N. J. “On the Habits of the Water-Shrew ” (Crossopus fodiens).  Proe. 
Zool. Soc., 1865, pp. 519-521. 
Barsoza pu Bocaag, Dr. J. V. ‘Sur quelques Mammifeéres rares et peu connus 
d'Afrique Occidentale qui se trouvent au Muséum de Lisbonne.” (Bayona 
velox.) Proc. Zool. Soc., 1865, pp. 401-404. 
Branpt, J. F. “On Solenodon.” ‘Memoirs of the Imperial Academy of Sciences of 
St. Petersburg,’ 1832-3. 
Cours Exuiorr. “ Precursory Notes on American Insectivorous Mammals ;” with 
description of new species. U.S. Survey. 
Dosson, G. E., F.R.S. “A Monograph of the Insectivora.” London : 1882-3. 
Git, THEODORE. “ Synopsis of Insectivorous Mammals.” ‘ Bulletin of the Geological 
and Geographical Survey of the Territories ;’ No. 2, Second Series. Washington ; 
May 14, 1875. 
* The Metatheria (Marsupials) are now in hand; an account of their skull will form Part IV. The 
Prototheria (Monotremes) will not be delayed longer than is absolutely necessary; if possible, their 
skull will be described in Part V. 
