collected on the Red Sea. 
351 
121. Sterna, sp. 
122. Sterna minuta. 
In summer on the Red Sea, in small flocks from 3-6 birds. 
Dighes, Arab. 
123. Sterna senegalensts, Sw. 
In large flocks south of the tropic. Breeds socially on coral 
islands in July, August, and September. Abu-baten, Arab. 
124. Sterna meridionalis, Br. 
Near Massaua. 
125. Anous tenuirostris. 
Single individuals on the whole Red Sea. On my last voyage 
only south of 14° N.L., from the end of September. In 
countless numbers in the Gulf of Aden, where it breeds in the 
height of summer on the island of Bur-da-Rebschi; we could 
easily catch them with our hands. Length to the end of wing 
14" 13'"j wing 9” 6"'; tarsus 10"'. Gullet pale-yellow; inter¬ 
digital membranes dark yellowish-carneous. 
126. Phaeton /Ethereus. 
Singly or in small flocks of from three to six on the Dahalak 
Isles, near Amphila, Ras Belul, Aden, and about Bur-da-Rebschi. 
Manners and voice much like Sterna caspia. Appears to 
copulate while swimming, in the month of August. 
127. Dysporus sula. (L.) 
On the whole Red Sea, alone and in flocks .—El Smet, Arab. 
128. Sula helanops, Hartl., n. sp. (Plate X. fig. 2.) 
Mas ad .: Alba, subflavescens; rcmigibus, scapularibus tectrici- 
busque alarum extimis et rectricibus nigris, omnibus ad basin 
albidis vel pure albis; scapis infra albis; flexui-a ake alba; 
rostro viresccnti-flavo, basi nigro; periophthalmiis et mem- 
brana gulari rotundato-truncata nigris; iride rubescenti- 
flava; pedibus ceerulescenti-plumbeis, membranis obscurio- 
ribus, unguibus corneo-nigris, ad apicem albidis; digiti 
medii margine serrato toto albo. Long. 27-28" ; rostr. a 
rict. 41' 6'" ; rostr. a fr. 3" 9 ,,, ; al. 16-l64 ,/ ; caud. 8"; tars. 
2"; dig. med. c. ung. 3" 10"'-3"11'". .Tun. : Capite, collo et 
corpore supra fuliginosis; fascia nuchali pallidiore parum 
conspicua; plumis dorsi ad apicem et ad basin albidis; sub- 
