158 ZOOPHYTES. 



Quite simple or segregato-gemmate, rarely free; zoophytes hemi- 

 spherical. Tentacles oblong, subequal. Coralla having the calicles 

 stibturbinate, either circular or much compressed, sometimes mean- 

 dering ; Iamella3 nearly or quite entire ; cell very narrow at bottom. 



The Euphyllia? grow either solitary or in large convex cespitose 

 clumps, consisting of segregate polyps; and there is a gradual transi- 

 tion from the simple species to others with long sinuous cells (some- 

 times six inches in length), containing several confluent polyp-disks. 

 No species are known in which the cells are much less than half an 

 inch in their longest diameter, and their texture is generally firm, 

 breaking with difficulty, except at the margin. The lamella? are 

 usually large and evenly thin, and either have a straight or convex 

 margin ; and when the latter, they often so fill the cell that the bottom 

 is concealed from view : if the former, the bottom is still very narrow. 

 The exterior of the calicles, although sometimes spinuloso-striate, 

 is generally nearly or quite smooth. Even the free species are at- 

 tached when quite young, and often the scar of the fracture by which 

 they became free may be distinguished. Some of the species resem- 

 ble the Mussse and Caulastrsea3, but they are distinguished from the 

 former by their entire lamella?, and from the latter by their firmer 

 texture, and from both, by the large and broad lamellae nearly filling 

 the cell. 



These zoophytes have a wider range than the other Astraeidse, some 

 species occurring in different parts of the temperate zone. 



The compound Euphylliee have been united hitherto, since the 

 dismemberment of Lamarck's genus Caryophyllia, with the genus 

 Mussa the Lobophyllia of Blainville; and the simple species have 

 constituted a part of the bid genus Turbinalia. If a comparison be 

 made of the animals of these zoophytes (plate .6) with those of the 

 Mussa (plate 7), sufficient reason will be seen for the separation pro- 

 posed, which is farther strengthened by the characters of the coralla. 

 The genus Flabellum was instituted by Lesson for a recent free 

 compressed species (E. pavonina,) with a lunate outline. But the 

 rotund shapes pass into the compressed by gradual transitions, both 

 in this genus, and the genera Mussa and Manicina. The genus 

 Diploctenium, of Goldfuss, has been referred by Blainville to this 

 division of the genus. 



The descriptions beyond, are preceded by an enumeration of the 

 species, to show their arrangement, arid also to indicate, by an aster- 

 isk, those that have been examined by the author. 



