of certain Birds of Cuba. LY 
is constantly 7. In birds on the other hand, of all the ver- 
tebree, the cervical vary the most in number; and indeed, on 
the length and flexibility of the neck, which in this class are 
generally produced by an increase in the number of joints, de- 
pends much of the economy of the species. 
Number | Maximum num-| Minimum num-| Extent 
of species| ber of cervical | ber of cervical of Observations. 
examined. vertebra. vertebra, variation. 
1. Raprores. . 14 11 
Pandion. Buteo. 
2. INSESSORES . 2 13 
Corvus. Fringilla. t I have added one Rasorial 
bird, Columba passerina, to 
3. Rasorges . . 18 12 the number examined by Cu- 
Struthio. Col, passerina ¢. vier, because I find that it 
presents the minimum num- 
ber of cervical vertebra yet 
G : 9 : y 
4, GRALLATORES 19 12 observed in the order of Ra- 
Hemantopus. cna. 
5. NATATORES . 3 12 
y Larus. 
Here then, we first observe that the two Normal groups have 
the least number of cervical vertebra, and the three Aberrant 
the greatest. In the next place, we see that the variation in 
the number of cervical vertebree is least in the Raptores, and 
greatest in the Natatores. Unfortunately, however, the num- 
bers in two very remarkable genera, Gypogeranus and Tachy- 
petes*, are not known. The 
* Although this bird has only been of late years well known, the important affinity 
existing between the Raptores and Natatores was known to Hermann, who says, 
p. 145 :— Cataractes genus a cl. Brunnichio conditum precipué cera rostri basin 
tegente differt assimilis hac in re Falconibus. Poterit aded qui velit cum istis avibus 
conjungere, et e Falconibus precipué cum F. leucocephalo, qui simili feré modo con- 
generis Halicti parasitus est: de qua re vid. Catesby, et Cataractem Skuam haud 
secus ac Falcones rapacem esse terrestremque rapinam exercere et anates gallinas 
imo agnos predari Sibbaldus, Willughbeius, Brunnichius fidem faciunt.” And again, 
VOL. XVI. D p- 154, 
