218 WORMS. INFUSORIA. 80. 81. 



and lunate denticulate alternate ramifications growing 

 smaller towards the bottom. 



Sowerby Brit. Mi/cell \.p. 51. tab. 25. 



Stem long, reddish-grey, ending at top in a bony substance, with 

 very short ramifications. 



80. HYDRA. Polype. 



751. H. nitidis. Green, with about 10 arms shorter 

 -than the body. 



Adams and.Koznm. Microfc. p. 364. tab. 21./. 5. 



In ftagriant waters and slow ftreams, generally on the under sur- 

 face of aquatic plants, appearing like a tranfparent green jelly 

 when contracted ; when expanded it is a linear body, fixed at one 

 end, and furrounded at the other by 8-10 tentacula or arms pla- 

 ced in a circle round the mouth, and gradually producing its young 

 from the sides, which at first feem small protuberances, increasing 

 iQ length* till they afsume the form of the parent, and then drop- 

 " ping off. Like all its tribe, it has the power of reproducing parts 

 . L^hich have been deftroyed ; and if cut or divided in any direction, 

 each feparate part will become a perfect polype. 



752. H. grisea. Yellowish-grey, with about 7 arms 

 longer than the body. 



Adams and Kaznm. Microfc. p. 364. tab. ix.f. 6. 



In rivulets and ftagnant waters, tapering towards the bafe, with 

 fometimes 12 arms or tentacula. 



753. H.fusca. Grey-brown, with about 8 arms, many 

 times as long as the body. 



Adams and Kanm. Microfc. p. 363. tab. 21. f. 7. 8. 



In fresh waters, a little tapering to the bafe., with very fine feta* 

 ccous and long tentacula or arms. 



ORDER V. INFUSORIA. 



SI. BRACHIONUS, 



754. Br. uvceolaris. Univalve, bell-shaped, with the shell 

 many-toothed at top, and rounded at the base : tail 

 long, cloven at the end. 



• Adams Microfc. p. 568. f. 22./. 36-38. t. vj.f. 56. 57. 

 Vorticella urceolaris. Donovan Br. Ins. t. 17. f. 1. 2. 



In stagnant waters, appearing to the naked eye as a final! white 

 fpeck : rotatory organ double, which can be protruded or con- 

 cealed at pleafure. ■ - . . 



755. Br. striates. Univalve, with an oval striate shell 

 6-toothed at top and entire at the base; without 

 tail. 



Adams Microfc. p. 364. tab. 27./^ 64. 65. 



In fait waterf tranfparent, crystalline, truncate on the forepart 

 and rounded behind: shell varying in form, with 12 longitude 



756 n Vr. TWptw. Bivalve, with the shell unarmed at 

 the top and 3-horned at the base? tail double. 



Adams Microfc. p. 566. tab. 27./. 59. 



In waters which have been kept fome time, very tranfparent and 

 Dearly triangular, with a double rotatory organ. 



