334 
into groups. These characters are most distinct in the centre of the 
disk, and towards the sides gradually merge into those presented by 
the thin portion of the linmg membrane (Pl. CLXVI. figs. 3 & 4). 
Thus these millstone-like bodies are formed of the same elements 
as the epithelial lining in other granivorous birds, merely modified 
so as to give them additional hardness. Perhaps naturalists who 
have an opportunity of observing the Nicobar Pigeon in a wild state, 
may be able to inform us whether any circumstances connected with 
its food or habits throw light upon the purpose of this peculiarity in 
its structure. I am not aware of a similar condition existing in any 
other bird; but in connexion with the subject it may be mentioned 
that Carus * has described and figured the lining membrane of the 
gizzard of the Fulmar Petrel (Procellaria glacialis) as studded with 
numerous horny tubercles, or teeth ; no account is given of their 
microscopical structure. 
EXPLANATION OF PLATES. 
PuaTEe CLXV. 
Fig. 1. Horizontal section of epithelial stratum of gizzard of Guinea-fowl (Nu- 
mida meleagris). 
. Similar section of follicular stratum of the same bird. 
. Vertical section of the lining membrane of the gizzard of the Common 
Fowl. 
= 
3 09 
wr 
A. Epithelial stratum. 
B. Follicular stratum. 
C. Fibrous stratum. 
D. Muscular coat. 
Fig. 4. Three of the cylinders drawn out from their follicles: treated with liquor 
potasse. From the Yellow-hammer (Eméeriza citrinella). 
Piate CLXVI. 
Fig. 1. Horizontal section of epithelial stratum of gizzard of the Common Pigeon 
(Columba livia), 
Fig. 2. Similar section of the follicular stratum of the same bird. 
Fig. 3. Horizontal section of the thin portion of the epithelial lining of the gizzard 
of the Nicobar Pigeon (Calenas nicobarica). 
Fig. 4. A similar section taken from near the centre of the disk. 
These sections are all represented as seen with a 4-inch object-glass, and me- 
dium eye-piece; with the exception of Fig. 3, Pl. CLXV., which is seen with a 
1-inch object-glass. 
4, On a New Form or GRALLATORIAL BIRD NEARLY ALLIED 
To THE CariAMa (DicHoLopHus cristaTus). By Dr. G. 
Hartiavus, ForergN MEMBER. 
Professor H. Burmeister of Halle, who has lately returned to 
Europe after an absence of about three years in the southern portion 
of South America, has communicated to me the following notice of 
a new species of Grallatorial Bird, very nearly allied to the Cariama, 
* Tab. Anat. Comp. Illust. fol. pars iv. 1835, tab. vi. 
