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POLYPI. 



The name of Polypiers has been given to the common parts of these 

 compound animals; they are always formed by deposition, and in layers like 

 the ivory of teeth, but are sometimes on the surface, and sometimes in the 

 interior of the compound animal. This difference of position has given rise to 

 the following families. 



FAMILY I. 



TUBULARII. 



THOSE of the first inhabit tubes of which the common gelatinous body 

 traverses the axis, like the medulla of a tree, and that are open, either on the 

 summit or sides, to allow the passage of the Polypi. 



Their more simple Polypi apear to be chiefly analogous to the Hydrae and 

 Cristatellae. 



TUBIPORA, Linnceus. 



Simple tubes of a stony substance, each containing a Polypus. These tubes 

 are parallel, and united from space to space by transverse lamina, which has 

 caused them to be compared to the pipes of an organ. 



It appears that we must approximate to the Tubipora certain fossil Coral- 

 liferi (Polypiers) also composed of simple tubes, such as the CATENIPORA, 

 Lam., where the tubes are deposited in lines that intercept vacant meshes; 

 the FAVOSITES, id., composed of crowded hexagonal tubes, &c. 



TUBULARIA, Linnceus, 



Simple or branched tubes of a horny substance, from the extremities of which 

 issue the Polypi. 



The Polypi of the fresh water Tubulariae Plumatella, Bosc. seem to be 

 closely approximated to the Cristatellse by the disposition of their tentacula. 



Certain species are found in France, that creep over the plants of stagnant 



waters. 



TUBULARIA MARINA. 



The Polypi of those that inhabit salt water have two ranges of tentacula, 

 the outer one forming radii, and the inner turning up into a tuft. 



TIBIANA, Lamouroujf. 

 Zigzag tubes presenting a small open branch at each angle. 



CORNULARIA, Lamarck, 



Where the tubes are conical, from each of which issues a Polypus with eight 

 dentated arms, like those of the Alcyoniae, Gorgonise, &c. In 



ANGUINARIA, Lamarck, 



The tubes are small, cylindrical, and adhere to a creeping stem, each one 

 opening laterally, and near the extremity for the passage of a Polypus. In 



