URCEOLARIA. POLYPI. 445 



V. socialis, Lam. Aggregated, tailed, club-shaped, with the disc ob- 

 lique. Inhabits marshes. Lam. ii. 48. 



V.fasciculata, Lam. Simple, green, campanulate ; margin reflect- 

 ed ; peduncle twisted. Inhabits rivers on Confervae. Lam. ii. 50. 



** Compound. 



V. pyraria, Lam. Compound, inversely conical, peduncle branch- 

 ed. Inhabits marshes, on the stalks of aquatic plants Mull. Inf. 

 pi. 46, fig. 1-4. 



V. ovifera, Lam. Compound, inversely conical, truncated ; pedun- 

 cle rigid, branched, fistulose ; ramuli oviferous, conglomerate. 

 Lam. ii. 50. 



Gen. 3. URCEOLARIA, Lam. 



Body free, contractile, urceolate, sometimes elongated, without 

 tail or peduncle; mouth terminal, dilated, furnished with 

 rotatory cilise. 



The microscopic animals of this genus swim freely in the water and with much 

 celerity, rarely fixing themselves by their posterior extremity. They withdraw or 

 protrude the ciliated and rotatory organs at theii anterior extremity at will, and move 

 them with great quickness. 



U. viridis, Lam. Cylindrical, uniform, opaque green. Inhabits 

 pure waters Lam. ii. 41. 



U. lunifera, Lam. Green, lunate, the middle of the margin behind 

 mucronate. Inhabits sea water. Lam. ii. 41. 



U. sacculus, Lam. Cylindrical ; aperture patulous j margin reflect- 

 ed. Inhabits marshes Lam. ii. 43. 



Gen. 4. FURCULARIA, Lam. 



Body free, contractile, oblong, furnished with a short or elon- 

 gated tail terminated by two points or two setae ; mouth pro- 

 vided with one or two ciliated and rotatory organs. 



F. larva, Lam. Cylindrical ; aperture lunated, and two caudal spines. 

 Inhabits sea water Lam. ii. 37- 



F. rediviva, Lam. (Vorticella rolatoria, Mull.) Cylindrical; tail 

 long. Inhabits pools of fresh water occasionally dry. Lam. ii. 39. 

 This is the species upon which Spallanzani made his experiments. 



Gen. 5. BRACHIONUS, Lam. 



Body free, contractile, almost oval, covered, at least partly, by a 

 transparent sheath, stiff and capsular, and furnished ante- 

 riorly with one or two ciliated and rotatory organs. 



The animals of this genus are very varied in point of form, which they change 

 by contraction. Some are deprived of a tail, but the greater portion have a simple 

 forked tail as the Furculariae. They live in the sea and fresh waters. The sheath or 

 shell, as it has been termed, is univalve or bivalve and capsular, according to the 

 species. 



* No tail 



B. striatus, Lam. Sheath or shell univalve, ovate, striated ; apex 

 with six teeth ; base entire, without tail. Sea water Lam. ii. 34. 



