o^eS OBSERVATIONS ON SUNDRY PLATES 



S E A P E N S 



Are a kind of marine infecfls, denominated from their refemblance to 

 a writing pen : the middle, which correfponds to the quill of the pen, is 

 a cartilaginous fubftance, in colour a clear brown; t\\t feathers of the 

 pen are whitifb, hollow like the body, but lefs folid, and partly allied to 

 the rays of fea ftars. The flefli of the animal occupies the whole j is at 

 lead the fize of a pen, often more. Is found in the Eaft Indies. 



The fecond differs from the former in having its lateral branches or 

 feathers furnilhed with other fmaller filaments, very thin : its colour varies 

 from red to white; the reddefl are moft defired. Is found as well in 

 the European as Indian feas. 



SEA URCHINS 



Are diftinguifhed from fea ftars by not being divided into rays, but 

 having numerous fpikes iffuing from fmall knobs difpofed over the fur- 

 face. If one of thefe points or fpikes be broken off, they regain the 

 dertciency. It has been hinted by fome, thatpofiibly they change their 

 fhell like crabs, &c. : it is certain that, when broken or pierced, they 

 quickly reftore it. Some are quite flat, and have no points. The mouth 

 is on one fide, the anus on the other» commonly diredlly oppofite. 



No. I. Is not round, but approaching to oval, flat on one fide, convex 

 on the other : its convex fide is reprefented ; its mouth is on the other 

 fide : colour brown. It has a great number of very fine and fliort afh- 

 coloured points: four deep fifTures on its convex fide, none on its flat 

 fide. Found at St. Domingo. 



No. 2. Is feenon that fide where its mouth is (which has five teeth) : 

 this urchin has two forts of points, one fliort, flatted, fmooth, and whitifh j 

 the other much longer, of an unequal or roughifli furface, and reddifh 

 colour. Is found in America, 



No. 3. Has a very great number of points, principally on the convex 

 face and fides j is of a fine violet colour. Found in the Mediterranean. 



No. 4. Is very convex on one of its faces''^ the opening feen is the 

 anus. The colours of this urchin are ftripes of green and white alter- 

 r>ately. The little knobs which cover its furface have ufuaily each a little 

 fpike of a quarter of an inch long; fome green, fome white : thefe break 

 off eafiiy when the animal is dead. Native of the Weft Indies. 



No. 5. Is extremely thin and flat; thickcft in the middle, thinncft 



toward 



