PEDICELLARIA. POLYPI. 443 



ORDER TV. POLYPI DENUDATI. 



Tentaculated polypi, not forming a polypiferous mass ; much 

 diversified in the form, the number, and situation of their ten- 

 tacula, and fixed either constantly or spontaneously. 



The genus Zoantha of Lamarck is placed by Cuvier in his class Acalepha. 



Gen. 1. PEDICELLARIA, Lam. 



Body fixed, formed of a stiff peduncle, terminated at the summit 

 by a club-shaped inflation ; club furnished with scales or ra- 

 diated beards ; mouth terminal. 



P. globifera, Lam. Head spherical; peduncle long, naked. Found 

 on Echini in the Northern seas Lam. ii. 64. 



Gen. 2. CORYNE, Lam. Hydra, Muller. 

 Body fleshy, pedunculated, terminated at the summit by an in- 

 flation like a vesicular club ; club furnished with scattered 

 tentacula ; mouth terminal. 



The polypi of this genus are often compound, and are found fixed on fuel and 

 other marine bodies. 



C. squamata, Lam. Peduncle simple ; club ovate-oblong ; base gem- 

 miferous ; tentacula setaceous. Northern ocean. Lam. ii. 62. 



C. setifera, Bosc. Club oblong, sessile ; tentacula setaceous, erect. 

 Found on Fucus natans Lam. ii. 62. 



Gen. 3. HYDRA, Lam. 



Body oblong, linear, or like a reversed cone, narrowed inferior- 

 ly, gelatinous and transparent, and fixed spontaneously by the 

 base ; mouth terminal, with a row of cirrous tentacula. 



Of all the polypi, the Hydrae have been most the subject of observation. They are 

 generally known by the name of Fresh Water Polypi or Polypi with arms. The experi- 

 ments made upon them by Trembley proved that at least, in one instance, animals may 

 be multiplied without the necessity of ova, or that the regenerative faculty resides in 

 every portion of their body. The body of the Hydrae is gelatinous, diaphanous, li- 

 near, or like a reversed cone. It is fixed spontaneously by its narrowed base upon 

 different bodies, and at its anterior extremity is a hollowed mouth surrounded by 

 from six to twelve filiform or setaceous cirrous tentacula, sometimes very long. The 

 species is multiplied by gemmae or buds, which spring up laterally on the body, and 

 which separate sooner or later to form new animals, according to the season. Ex- 

 periment has ascertained that if an Hydra be deprived of any part of its body it is 

 readily reproduced ; if cut in two each portion becomes a complete animal ; and if 

 separated into smaller parts each will form in two days a separate individual. Trem- 

 bley even turned one of these animals inside out as the finger of a glove may be 

 turned, without its ceasing to live and perform its animal functions. 



H. viridis, Lam. Body green, transparent, short, with from eight 

 to ten tentacula about the length of the body. Fresh waters, on 

 the leaves of aquatic plants. About an inch high. Lam. ii. 60. 



H. grisea, Lam. Body grayish ; tentacula varying in number. In- 

 habits fresh waters. Lam. ii. 60. 



H. lutea, Lam. Yellowish, branched, head large, with about ten 

 tentacula. Inhabits the sea, on Fuci. Lam. ii. 60. 



