PIS 



PIS 



of a somewhat dull appearance. On the 

 third day, it assumes the appearance of 

 a thickish mass, detached on one side, and 

 on the other strongly adhering- to the yolk, 

 and presenting the contour of the heart, 

 which at this period receives an increase 

 of motion, while the disengaged extremity, 

 which forms the rudiments of the tail, is 

 perceived to move at intervals. On the 

 fourth day, the pulsations of the heart, 

 and the movements of the whole body 

 occur in quicker succession. On the fifth, 

 the circulation of the humours in the ves- 

 sels may be discerned, when the fish is in 

 a particular position. On the sixth, the 

 back-bone may be distinctly recognised. 

 On the seventh, two black points, which 

 are the eyes, and the whole form of the 

 animal, are visible to the naked eye. Al- 

 though the yolk gradually diminishes as 

 the embryo enlarges, the included animal 

 cannot yet stretch itself at length, but 

 makes a curve with its tail. Its motions 

 are then so brisk, that when it turns its 

 body, the yolk turns with it ; and these 

 motions become more and more frequent, 

 as the moment of birth, which happens 

 between the seventh and ninth day, ap- 

 proaches. By repeated strokes of the tail, 

 the covering of the egg at length gives 

 way, and the fish comes forth, first by the 

 tail, redoubling its efforts, till it detach 

 its head ; and then it moves nimbly, and 

 at liberty in its new element. 



Fishes have different seasons for depo- 

 siting their spawn. Some, which live in 

 the depths of the ocean, are said to choose 

 the winter months ; but, in general, those 

 with which we are acquainted choose the 

 hottest months in summer, and prefer such 

 water as is somewhat tepified by the 

 beams of the sun. They then leave the 

 deepest parts of the ocean, which are the 

 coldest, and shoal round the coast, or 

 swim up the fresh-water rivers, which are 

 warm as they are comparatively shallow, 

 depositing their eggs where the sun's in- 

 fluence can most easily reach them, and 

 seeming to take no farther charge of their 

 future progeny. Of the eggs thus depo- 

 sited scarcely one in a hundred brings 

 forth an animal, as they are devoured by 

 all the lesser fry which frequent the 

 shores, by aquatic birds near the margin, 

 and by the larger fish in deep water. Still, 

 however, the sea is amply supplied with 

 inhabitants: and notwithstanding their 

 own rapacity, and that of various tribes 

 of fowls, the numbers that escape are 

 sufficient to relieve the wants of a con- 

 siderable portion of mankind. Indeed, 

 when we consider the fecundity of a sin- 



gle fish, the amount will seem astonish- 

 ing. If we should be told, for example, 

 that a single being could in one season, 

 produce as many of its kind as there are 

 inhabitants in England, it would strike us 

 with surprise : yet the cod annually 

 spawns, according to Lewenhoeck, above 

 nine million of eggs contained in a single 

 roe. The flounder is commonly known to 

 produce above one million; and the mac- 

 karel above five hundred thousand ; a 

 herring of a moderate size will yield at 

 least ten thousand ; a carp, of fourteen, 

 inches in length, contained, according to 

 Petit, two hundred and sixty-two thou- 

 sand two hundred and twenty-four ; and 

 another, sixteen inches long, contained 

 three hundred and forty-two thousand one 

 hundred and forty-four ; a perch deposit 

 ed three hundred and eighty thousand 

 six hundred and forty ; and a female stur- 

 geon, seven million six hundred and fifty- 

 three thousand two hundred. The vivi- 

 parous species are by no means so fruit- 

 ful ; yet the blenny brings forth two or 

 three hundred at a time, all alive, and 

 playing round the parent together. 



PISCES, in astronomy, the twelfth sigji 

 or constellation of the zodiac. The stags' 

 in Pisces, in Ptolemy's catalogue, arfe 

 thirty-eight ; in Tycho's thirty-three ; and 

 in the Britannic catalogue one hundred 

 and nine. 



PISCIDA, in botany, a genus of the 

 Diadelphia Decandria class and order. 

 Natural order of Papilionaceae, or Legumi- 

 nosse. Essential character : stigma acute; 

 legume winged four ways. There are two 

 species, viz. P. erythrina, Jamaica dog- 

 wood tree, and P. earth aginensis, both na- 

 tives of the West Indies. 



PISCIS austmtis, the southern fish, is a 

 constellation in the southern hemisphere, 

 being one of the forty-eight constellations 

 mentioned by the ancients. The star toma- 

 haut, of the first magnitude, is in the 

 mouth of this fish. Piscis volans, the 

 flying fish, is a small constellation of the 

 southern hemisphere, added by the mo- 

 derns ; it contains eight stars, but is not 

 visible in our latitude. 



PISONIA, in botany, so named in ho- 

 nour of William Piso, a physician, a ge- 

 nus of the Polygamia Dioecia class and 

 order. Natural order of Nyctagines, 

 Jussieu. Essential character: calyx scarce- 

 ly any: corolla bell shaped, five-cleft; 

 stamina five or six ; pistil one ; capsule 

 superior, one-ceiled, valveless : male and 

 female on the same or on different plants. 

 There are five species. 



PISTIACIA, in botany, a genus of the 



