II6 DICTIONARY OF BIRDS 
be allied, only rather more remotely, to the Turdidea—for Thrushes and 
Chats are inseparable, and therefore this connexion must drag down the 
Thrushes in the scale. Let it be granted that the more highly-developed 
Thrushes have got rid of the low “ Struthious ” features which characterize 
their Australian relatives, the unbroken series of connecting forms chains 
them to the inferior position, and of itself disqualifies them from the rank 
so fallaciously assigned to them, Nor does this consideration stand alone. 
By submitting the Thrushes and allied groups of Chats and Warblers to 
other tests we may try still more completely their claim to the position 
to which they have been advanced. 
Without attaching too much importance to the systematic value which 
the characters of the nervous system afford, there can be little doubt that, 
throughout the Animal Kingdom, where the nervous system is sufficiently 
developed to produce a brain, the creatures possessing one are considerably 
superior to those which have none. Consequently we may reasonably 
infer that those which are the best furnished with a brain are superior to 
those which are less well endowed in that respect, and that this inference 
is reasonable is in accordance with the experience of every Physiologist, 
Comparative Anatomist and Paleeontologist, who are agreed that, within 
limits, the proportion which the brain bears to the spinal marrow in a 
Vertebrate is a measure of that animal’s morphological condition. These 
preliminaries being beyond contradiction, it is clear that, if we had a series 
of accurate weights and measurements of Birds’ brains, it would go far to 
help us in deciding many cases of disputed precedency, and especially such 
a case as we now have under discussion. 'To the dispraise of Ornithoto- 
mists this subject has never been properly investigated, and of late years 
seems to have been wholly neglected. The lists given by Tiedemann 
(Anat. und Naturgesch. der Vogel, i. pp. 18-22), based for the most part 
on very ancient observations, are extremely meagre, and the practical 
difficulties of carrying on further research, though not insuperable, are 
considered to be great ;1 but, so far as those observations go, their result 
is conclusive, for we find that in the Blackbird, Turdus merula, the pro- 
portion which the brain bears to the body is lower than in any of the 
eight species of Oscines there named, being as 1 is to 67. In the Red- 
breast, Hrithacus rubecula, certainly an ally of the Turdidz, it is as 1 to 
32; while it is highest in two of the Finches—the Siskin, Carduelis 
spinus, and the Canary-bird, Serinus canarius, being in each as 1 to 14. 
The signification of these numbers needs no comment to be understood. 
Evidence of another kind may also be adduced in proof that the 
high place hitherto commonly accorded to the Jurdide is undeserved. 
Throughout the Class Aves it is observable that the young when first fledged 
generally assume a spotted plumage of a peculiar character 2—nearly each 
of the body-feathers having a light-coloured spot at its tip—and this is 
1 One of the latest writers on the brain of Birds (Zeitschr. fiir wissensch. Zoolog. 
xxxvili. pp. 430-467, pls. xxiv. xxv.), though giving tables of the proportion of its 
several parts in various genera, unfortunately gives none of the proportion of the 
whole to the body. 
2 Blyth in 1833 seems to have indicated this well-known fact as affording a 
character in classification (eld Nat. i. pp. 199, 200). Nearly 50 years after it was 
claimed as the discovery of another writer. 
