

Australian Natural History. 1489 



open spaces to feed during morning and evening ; I believe it also 

 feeds during the night, for while encamped on Mosquito Island, at 

 the mouth of the Hunter River, I have frequently after dark heard 

 the pat-pat of leaping kangaroos, and only this and another, the 

 black wallaby [H. ualabatus), are found there. It has a form like a 

 hare, is extremely vigilant and swift, making short leaps, with tail ex- 

 tended and nearly touching the ground. If disturbed, it hops off 

 with great rapidity, for a few yards, and then, if not pursued, stops 

 and raises itself to a semi-erect position, attentively listening. If any 

 noise is made, even the breaking of a twig or the rustling of a dead 

 leaf, off skips the pademelon a little further, and then halts as before. 

 I have sometimes come upon them while squatted under a heap of 

 dead branches, expecting me to pass, but in general they are off 

 upon the sound of approaching footsteps ; I have also occasionally 

 started them from off fallen logs. The young, from the pouch, if suf- 

 ficiently grown to be able to eat grass, are easily reared, and soon be- 

 come quite familiar. 



Note on species of Velella and Glaucus. — One day while becalmed 

 in the South Atlantic in lat. 23° S. and long. 25° W., with numbers 

 of marine animals in the water all around, I caught some Velellse and 

 a Glaucus, descriptions of which I subjoin, as I cannot identify the 

 species. 



Velella mutica. The Velella, known to seamen as the " sallyman," 

 is sure, next to the Physalis or " Portuguese Man-of-war," to attract 

 the attention of the most incurious voyager in those seas which it fre- 

 quents, from its beautiful blue colour and curious mechanism ; the 

 transverse membranous crest on the back acting as a sail, by commu- 

 nicating a slow, rotatory motion while drifting to leeward. Length 

 1 T 5 T inches, breadth 44, length of cartilaginous disk 1 inch, of ridge 

 on ditto 1 T \ inches, height of ridge T 6 , inches. Skeleton composed of 

 two portions, one, which may be called the disk, is horizontal, mem- 

 branous, with an umbo and about twenty parallel concentric rugae ; it 

 is crossed in its short diameter by a waving sulcus, with a slight 

 emargination at its two extremities. Along the entire length there ex- 

 tends, in a slightly waving manner, a vertical, membranous, or almost 

 horny transparent crest, rising to the height of half an inch, with a 

 slightly waved margin, and a central projection with numerous, very 

 faint, concentric, and still more obsolete centripetal rugae. To the 

 crest is attached a slight, minutely granulated, membranous fringe, 

 extending about a line beyond the membranous border. To the 

 lower surface of the disk is likewise attached a horizontal gelatinous 

 iv 5 x 



