550 



Crcagurp of Natural 



about fifteen inches long, or nearly the size 

 of the Red Grouse. The bill is black ; orbits 

 bright red ; the tipper parts of the body pale 

 brown or ash, mottled with small dusky 

 spots and bars ; the head and neck with 

 broad bars of black, rust-colour, and white : 

 the tinder parts are white, as are also the 

 wings, excepting the shafts of the quills, 

 which are black. In winter this plumage is 

 changed to a pure white, except that in the 

 male there is a black line between the bill 



and the eye. The tail consists of sixteen 

 feathers ; the two middle ones ash-coloured 

 in summer, and white in winter ; the next 

 two are slightly marked with white near 

 the ends, the rest are wholly black ; and 

 the feathers incumbent on the tail, and 

 nearly covering it, are white. The Ptar- 

 migan, or White Grouse, is fond of lofty 

 situations, and is found in most of the 

 northern parts of Europe, even as far as 

 Greenland : in this country it is only to be 

 met with on the summits of some of our 

 highest hills, chiefly in the Highlands of 

 Scotland, in the Hebrides and Orkneys, and 

 sometimes, but rarely, on the lofty hills of 

 Cumberland and Wales. The female lays 

 eight or ten eggs, which are white, spotted 

 with brown : she makes no nest, but deposits 

 them on the ground. These birds fly in 

 small flocks, and Iced on the wild produc- 

 tions of the hills : their flesh is dark-coloured, 

 and has somewhat the flavour of the hare. 



PTERICIITIIYS, or WINGED FISH. 



A fossil genus of fish found in the Old Red 

 Sandstone by Mr. Hugh Miller, and de- 

 scribed by him in his interesting geological 

 work. " Imagine," says he, " the figure of 

 a man rudely drawn in black on a gray 

 ground, the head cut off by the shoulders, 

 the arms spread at full, as in the attitude of 

 swimming, the body rather long than other- 

 wise, and narrowing from the chest down- 

 wards ; one of the legs cut away at the hip 

 joint, and the other, as if to preserve the 

 balance, placed directly under the centre of 

 the figure, which it seems to support. Such, 

 at a first glance, is the appearance of the 

 fossil. The body was of very considerable 

 depth, perhaps little less deep proportionally 

 from back to breast than the body of the 

 tortoise ; the under part was flat, the upper 



rose towards the centre into a roof- like 

 ridge, and both under and upper were co- 

 ith a strong armour of bony plates, 



ered 



which, resembling more the plates of the 

 tortoise than those of the crustacean, re- 

 ceived their accessions of growth at the 

 edges or sutures. The plates on the under 

 side are divided by two lines of suture, which 

 run, the one longitudinally through the 

 centre of the body, the other transversely, 

 also through the centre of it ; and they cut 

 one another at right angles, were there not 

 a lozenge-shaped plate inserted at the point 

 where they would otherwise meet. There 

 are thus five plates at the lower or belly 

 part of the animal. They are all thickly 

 tuberculated outside with wart-like promi- 

 nences ; the inner present appearances in- 

 dicative of a bony struc.ttire. The plates on 

 the upper side are more numerous and more 

 difficult to describe, just as it would be diffi- 

 cult to describe the forms of the various 

 stones which compose the ribbed and pointed 

 roof of a Gothic cathedral, the arched ridge 

 or hump of the back requiring, in a some- 

 what similar way, a peculiar form and ar- 

 rangement of plates. The apex of the ridge 

 is covered by a strong hexagonal plate, fitted 

 upon it like a cap or helmet, and which 

 nearly corresponds in place to the flat cen- 

 tral part of the under side. There runs 

 around it a border of variously-formed 

 plates, that diminish in size and increase in 

 number towards the head, and which are 

 separated, like the pieces of a dissected map, 

 by deep sutures. They all present the tu- 

 berculated surface. The eyes are placed in 

 front, on a prominence much lower than the 

 roof -like ridge of the back ; the mouth seems 

 to have opened, as in many fishes, in the 

 edge of the creature's snout, where a line 

 running along the back would bisect a line 

 running along the belly ; but this part is less 

 perfectly shown by my specimens than any 

 other. The two arms or paddles are placed 

 so far forward as to give the body a dispro- 

 portionate and decapitated appearance. 

 From the shoulder to the elbow, if I may 

 employ the terms, there is a swelling mus- 

 cular appearance, as in the human arm ; 

 the part below is flattened so as to resemble 

 the blade of an oar, and it terminates in a 

 strong sharp point. The tail the one leg on 

 which, as exhibited in one of my specimens, 

 the creature seems to stand is of consider- 

 able length, more than equal to a third of the 

 entire figure, and of an angular form, the 

 base representing the part attached to the 

 body, and the apex its termination. It was 

 covered with small tuberculated rhomboidal 

 plates, like scales ; and where the internal 

 structure is shown, there are appearances of 

 a vertebrated bone, with rib-like processes 

 standing out at a sharp angle." The spe- 

 cies has been named by Agassiz, P. JUilleri 

 In honour of the author of "The Old Red 

 Sandstone " and the " Asterolepis." 



PTEROCERAS. A genus of Molluscouo 



animals, inhabiting th 



. genus o 

 e Indian 



Ocean. The 



head is furnished with a proboscis and two ! 

 tentacula, which are short ; the eyes are 

 situated on foot-stalks longer than the ten- ' 



