544 



(Erotfurp of Natural ^t 



of air. By means of this organ, it appears, 

 they either force out the air, or compress it 

 into a much smaller compass, when they 

 wish to sink ; and distend the sac when they 

 desire to rise. From the under side of the 

 air-sac there is a mass of short flask-shaped 

 appendages hanging down, which are ter- 

 minated by suckers, with an orifice in each. 

 Whilst the lower surface of the air-sac is 

 not itself above six inches from one end to 

 the other, the tentacula sometimes hang 

 down like fishing lines, to an extent of fifteen 

 or sixteen feet. They generally possess an 

 active stinging power, and are also very 



contractile, so that they are able to draw up 

 the prey which they have attacked. It 

 would seem that the short suckers are at- 



tached to the bodies of animals thus en- 

 trapped ; and that the Physalia derives its 

 nourishment by imbibing their juices 

 through the pores of these numerous cirrhi. 



PORTUNID^E, or FIN-FOOTED 

 CRABS. A family of Brachyurous Crus- 

 tacea mostly found in the seas of warm cli- 

 mates, and vulgarly called Paddling Crabs. 

 They are in general remarkable for the 

 flatness and great transversed extent of their 



SFOTTBD-FIN 



carapace, which in hreadth is more than 

 double its length. Their general form does 

 not ordinarily differ much from that of the 

 greater part of the Cancerians. The last 

 pair of legs is flat and oar-like , a structure 

 which enables these crabs to swim with great 

 ease : hence some of the species are found 

 at a great distance from land. Some of 

 these are found on our own coasts, one of 

 which, the small common Crab, is hawked 

 about London, and eaten by the poorer 

 classes ; but the one here figured is the 

 Lupa cribraria, which inhabits the coasts of 

 Brazil : it is about three inches in length ; 

 of a yellow colour, with numerous whitish 

 spots. 



PORZANA. A genus of birds belonging 

 to the family Rallidce; by most authors it is 

 included in the genus Ortygomctra, the type 

 of which is our COMMON CRAKE (O. crex). 

 To it belongs the SPOTTED GAI.LINULE (O. 

 Porzana), a species which is not very common 

 in Britain ; on the upper side it is of an 

 olive- brown colour, with dusky streaks and 

 white spots; beneath, it is of an ashy-olive, 

 with white spots. Mr. Gould describes a fine 

 species in his Australian Birds. This is 

 the PORZAXA (Ortyg.) FLUMINEA, or SPOT- 

 TED WATER-CRAKE. This Grallatorial bird 

 inhabits various parts of Australia ; and, like 



its European ally (Ralhts porzana of I/ln- 

 nseus) frequents morasses, reed-beds, and the 

 neighbourhood of rivers clothed with dense 

 herbage ; but the uniform gray tint of its 

 breast and under surface, and its smaller size, 

 are characters by which it is readily distin- 

 guished from it. The whole of the upper 

 surface is of an olive colour, with a broad 

 stripe of blackish brown down the centre, 

 and two oval spots of white, bounded above 

 and below with black on the margin of each 

 web of every feather ; primaries and secon- 

 daries brown ; tail dark brown, margined 

 with lighter brown, and with an indication 

 of white spots on the extreme edge ; face, 

 throat, chest, and upper part of the abdomen 

 dark slate-gray ; lower part of the abdomen 

 and flanks grayish-black, crossed by narrow 

 irregular bars of white ; under tail coverts 

 white ; bill orange-red at the base, and dark 

 olive-green for the remainder of its length ; 

 feet dark olive-green. 



POTOO. (Nyctibim Jamaicensis.') This 

 bird is a native of Jamaica, and belongs to 

 the CaprirmtJgidce family. It is sixteen 

 inches long, and in expanse from the tip of 

 each wing thirty-three inches and a half. 

 Plumage mottled with black, brown, gray, 

 and white ; the white prevailing on the 

 tertiaries, tertiary-coverts, and scapulars, the 

 black upon the primaries and their coverts ; 

 ihe tail-feathers barred transversely with 

 black on a gray ground, and delicately mot- 

 tled ; tail broad, very slightly rounded : 

 inner surface of the \yings black, spotted 

 with white. On each side of the throat is a 

 black streak ; a bay tint prevails on the 

 breast ; and some of the feathers there have 

 broad terminal spots of black. Under parts 

 pale gray ; but every feather of the whole 

 plumage is marked with a black stripe down 

 the centre. The beak is black ; the tongue 

 sagittiforin, sleuder towards the tip, re- 

 verted barbs along the edges. Irides orange- 

 coloiired or brilliant straw-colour. Feet 

 whitish, and scurfy. 



" The Potoo is not unfrequently seen in 

 the evening, taking its station soon after 

 sunset on some dead tree or fence-post, or 

 floating by on noiseless wing, like on owl, 

 which the common people suppose it to be. 

 Its plumage has the soft, puffy, unwebbed 

 character which marks that of the owls, and 

 which prevents the impact of its wings upon 

 the air from being audible, notwithstanding 

 the power and length of those organs. Now 

 and then it is seen by day ; but it is half 

 concealed in the bushy foliage of some thick 

 tree, which it can with difficulty be induced 

 to quit, distrustful of its powers by day. As 

 it sits in the fading twilight, it ever and 

 anon utters a loud and hoarse ho-koo, and 

 sometimes the same syllables are heard, in 

 a much lower tone, as if proceeding from 

 the depth of the throat. * * * If I may 

 judge of the habits of the Potoo (observes 

 Mr. Gosse) from what little I have observed 

 of it when at liberty, and from the manners 

 of my captive specimen, I presume that, 

 notwithstanding the powerful wings, it flies 

 but little ; but that, sitting on some post of 

 observation, it watches there till some ere- 



