PHALACROCOKACID^ PLOTUS 11 



or on a sand bank sunning itself with outstretched wings drooping 

 on either side, and is most active early and late. 



The Eeed Duiker was found breeding on the Berg Kiver in^very 

 large numbers in September by Mr. Layard, and I have myself taken 

 eggs on Dassen Island in July, and on Schaap Island in Saldanha 

 Bay in September, while the Woodwards, when at St. Lucia Lake 

 in Zululand, obtained in June only young birds and no eggs. The 

 nests are composed of sticks and stalks, and several are often found 

 so close together as to be partly interwoven ; they are placed on 

 low rocks usually in crevices on Dassen Island, but where there are 

 trees or low bushes, as at Berg Eiver or St. Lucia, these are made 

 use of. The eggs are two or three in number and resemble those 

 of the other Duikers, except that they are a good deal smaller, 

 measuring on an average 1'90 x I 1 27. 



Subfamily II. PLOTIN^E. 



Genus I. PLOTUS. 



Type. 



Plotus, Linn. Sysl. Nat. i, p. 218 (1766) P. anhinga. 



Bill slender, straight and sharp pointed, the tips of both the 

 mandibles serrated ; nostrils rudimentary ; head and neck slender 

 and snakelike ; wings long and pointed, the second and third 

 primaries the longest ; scapulars elongate, lanceolate and pointed ; 

 tail long, of twelve feathers, graduated and rigid, the webs of the 

 two central feathers being transversely corrugated ; tarsus very 

 short, feet completely webbed, outer toe the longest ; claw of the 

 middle toe pectinated. 



The anatomical peculiarities characteristic of this genus and 

 subfamily are doubtless special modifications correlated with the 

 curious habits of these birds. The first eight cervical vertebrae 

 (including the atlas and axis) when placed in a natural position 

 forma strong curve with the concavity directed forwards; the eighth 

 vertebra, which is very long, is almost parallel with the bill when 

 held horizontally ; on the dorsal surface of the ninth vertebra is a 

 transverse loop, termed Donitz's bridge, ossified in all the species 

 except P. anhinga ; through this passes the tendon of the longus 

 coli posterior muscle to be inserted in the second, third, and fourth 

 vertebras ; the longus colli anterior is a powerful muscle ending in 



