“The result of the dissection of the head of the _Rhynchops_, comparatively with that of the head of the duck, is not what you anticipated. The facial, or sensitive branches of the fifth pair of nerves, are very small; the third division in particular, is filamentary, and I have not been able to trace it beyond the soft integument at the angles of the mouth. After removing with care, the thin horny covering of the beak, I cannot perceive any trace of those nervous expansions which are so remarkable in the lamelli-rostral aquatic birds; and which in them supply the tooth-like process, and soft marginal covering of the mandibles. Nevertheless, when we remember how sensitive a hair is, through the nerve situated at its base, though without any in its substance, it would not be safe to deny altogether, a sensitive faculty in the beak of the Rhynchops.” M. Lesson (Manuel d’Ornithologie, vol. ii. p. 385.) has stated, that he has seen these birds opening the shells of the Mactræ, buried in the sandbanks on the coast of Chile. From their weak bills, with the lower mandible so much produced, their short legs and long wings, it seems very improbable that this can be a general habit, although it may sometimes be resorted to. Wilson, who was well acquainted with this bird, does not believe “the report of its frequenting oyster beds, and feeding on these fish.” The existence, however, of this same report in the United States, makes the question, whether the Rhynchops does not sometimes turn the peculiar structure of its beak to this purpose, worthy of further investigation. VIRALVA ARANEA. _G. R. Gray._ Sterna aranea, _Wils._ Am. Orn. pl. 72. f. 6. My specimen was procured at Bahia Blanca, in Northern Patagonia. I may here observe, that many navigators have supposed that terns, when met with out at sea, are a sure indication of land. But these birds seem not unfrequently to be lost in the open ocean; thus one (_Megalopterus stolidus_) flew on board the Beagle in the Pacific, when several hundred miles from the Galapagos Archipelago. No doubt, the remark made by navigators, with respect to the proximity of land where terns are seen, refers to birds in a flock, fishing, or otherwise showing that they are familiar with that part of the sea. I, therefore, more particularly mention, that off the mouth of the Rio Negro, on the Patagonian shore, I saw a flock (probably the _Viralva aranea_) fishing seventy miles from land: and off the coast of Brazil a flock of another species, 120 from the nearest part of the coast. The latter birds were in numbers, and were busily engaged in dashing at their prey. MEGALOPTERUS STOLIDUS. _Boie._ Sterna stolida, _Linn._ Syst. i. 227.