502 CLASS ECHINODERMATA. 
agreeable to view. ‘Their propagation goes on by eggs, or 
gemme, which are developed in some cellules, larger than the 
others, and of different forms. 
The various directions of their cellules, have given rise to 
their distribution into several subdivisions. 'Thus when the 
little cells are ranged on one side only over the branches, they 
are then the AGLAOPHENIA of M. Lamouroux, which M. 
de Lamarck names PLUMULARIA. (Sert. Myriophyllum, 
Gm., &c.) 
When they are assembled in certain places, like the small 
tubes of an organ, they constitute AMATIA, Lamour., or 
SERIALARIA, Lam. (Sertularia lendigera, Ellis.) 
We may distinguish from them the species in which the 
cellules thus disposed, surround the stem with a spiral figure. 
When the cellules are placed around the stem, in horizon- 
tal rings, these are the ANTENNULARIA, Lam., which M. 
Lamouroux had named CALLIANYRA, and has since changed 
into NEMERTESIA. (Sertularia antennina, Gm. &c.) 
Thus the name of SERTULARIA proper, remains to those 
species only in which the cells are on both sides of the stem, 
whether opposed, Sert. abietina, Gm., &c. or alternate. 
Sertularia operculata, Ell., &c. M. Lamouroux distinguishes 
the first under the name of DYNAMENES. 
The extreme smallness of the cellules has also caused him 
to establish the genus THamA, (Sertularia heelicina, Gm. &c.) 
The second family is that of 
POLYPI CELLULOSI, 
In which each polype is adherent in a corneous or calcareous 
cell with their parietes, and does not communicate with the 
others but by an external tunic very much attenuated, or by 
fine pores, which traverse the parietes of the cellules. These 
polypi have a general resemblance to the hydrz. 
