192 Tra ns ac tions. — Zoology. 



9th February. — I watched for a considerable time from the 

 bows of the ship, which afforded an excellent post of observa- 

 tion, the movements of the Flying-fish. There are two kinds 

 in this part of the ocean, a larger and a smaller, both belong- 

 ing to the genus Exocoatus. One of each species came on 

 board, at different times, so I had an opportunity of examining 

 them. The larger one measures, in extreme length, 19in. ; 

 spread of pectoral fins, 23in. ; length of pectoral fins, 10-75in. 

 The smaller one measures 9in., with a spread of 10-75iu., the 

 length of the pectoral fins being 4-75iu. There are important 

 structural differences in the two forms, and their colouring 

 also distinguishes them. The smaller species, which is by far 

 the more abundant of the two, has the upper surface dark 

 indigo-blue, the sides of the body bright cobalt, the under sur- 

 face w^hite, and the eyes lustrous black, with orbits of iri- 

 descent blue ; the fins are bluish-grey with transparent colour- 

 less webs, and the tail is greyish-white. The larger species is 

 naturally more vigorous on the wing and capable of a more 

 sustained flight than the smaller kind. The latter performs a 

 flight of twenty to thirty yards, and then drops abruptly into 

 the sea. As a rule the flight is direct, even against the wind ; 

 but occasionally I observed a vigorous flyer make a half-circuit, 

 and I observed one turn back slightly on its course. Immedi- 

 ately after rising out of the water the fish often dips to the 

 surface, appa.rently for the purpose of gaining fresh impetus 

 by means of the produced lower vane of the tail, which is the 

 only part that touches the water. The wings do not vibrate, 

 but are perfectly rigid. The tail is used a& a means of propul- 

 sion not only at starting, when it ploughs a little course in 

 the water, but at intervals during the flight, when the fish dips 

 to the surface, and, touching the water with this member, 

 seems to be impelled forward again. About 11 o'clock this 

 morning, when about six hundred miles from Ascension Island, 

 and eight hundred miles from the coast of Africa, a pair of 

 large Grey Petrels passed our weather-bow, flying low and 

 rapidly, but we saw nothing more of them. 



10th and 11th February. — No birds, but calm and hot days, 

 with Flying-fish in large shoals. The nights are clear and 

 beautiful, the unusual brilliance of the starlight being no doubt 

 due to the great rarity of the atmosphere. Orion's Belt, to 

 my mind the most beautiful of the constellations, was specially 

 brilliant ; and on the evening of the 10th sve had our first 

 view of the Southern Cross. 



12th February. — The wind strengthened during the night, 

 and now we are experiencing the steady N.E. trades, which 

 will probably go through to the Cape with us. The entire 

 absence of birds is very remarkable, for we have had all kinds 

 of weather : first of all the warm Guinea current, of mysterious 



