128 Baron 11. K. von Wartliauscn on the Nidijicutiun 



length reaches 25-29, their breadth 17|-18| Imcs ; their 

 weight amounts to 54-70, generally to 60 grains. The ground- 

 colour is greenish- white, greenish -grey, reddish- white, incar- 

 nate, or violet-rose. The greenish specimens have, as in Alca 

 torch, large blackish-brown burnt spots and grey clouds ; the 

 reddish ones mostly smaller, rounded, sometimes also burnt 

 spots, the colour changing from the centre to the margin as 

 stated above, and frequently short and numerous flourishes of a 

 chestnut-brown (rarely entirely black or light-brown) nearly red 

 colour. In several specimens the flourishes are as large and as 

 well-developed as in the finest eggs of Uria troile. Bluish- 

 grey markings lie deeper in the substance of the shell, and 

 sometimes little conspicuous in the whitish specimens ; they 

 generally correspond to the external spots in size, form, and 

 situation, and appear rarely as larger clouds in dotted eggs. 

 One specimen is uniform greenish-white. Reddish eggs, held 

 against a light, are transparent yellowish-green, greenish ones 

 bluish-green. The granulation is strong, coarse, flat, labyrinth- 

 ine, with rounded pores and deep pits. 



7. Angus tenuirostris. Leach. {Sterna senex, Cranch.) 

 This species, observed by Biippell in the Red Sea, and by 

 others in West Africa, was found by Heuglin in about 11° N.L., 

 on the Somali (Somauli) coast, on Bur-da-Rebschi (Arab. Djebel- 

 Tiur), a rocky and very steep island, about 500 feet high. 

 There thousands of them breed, the most efficient producers of 

 the guano collected by the Somali fishermen, who state that 

 their breeding- season is in May or June. 



Heuglin found (14th Nov. 1857) some old eggs (which ad- 

 mitted of an mi perfect preservation only, and some of which 

 were discoloured by the light-brown adherent guano) on the 

 surface and on the clefts of the rocks. Eight specimens were 

 procured, of an elongate-^ovate form, having a length of 21 to 24 

 lines, and a breadth of 14 to 16 lines. On the average they are 23 

 lines long and 15 broad; the longest is the broadest. They are 

 closely allied to the eggs of Anous stolidus with regard to size 

 and coloration. They have a pale reddish-yellow, flesh-coloured 

 or whitish ground-colour, and either only a few spots of rather 



