490 ZOOPHYTES. 



The surface is seldom covered with regular calicles ; and when so, 

 the species differ from Madrepora in being simply glomerate or 

 explanate, and the calicles are mostly angular or somewhat irregular. 



The cells in most ManoporEe are either wholly immersed or sur- 

 rounded by a few ragged points, the rudiments of a calicle. These 

 points are sometimes coalescent in series, and form small ridges over 

 the surface. The surface in certain other species has scattered pro- 

 minences wart-like in shape between the cells; and there is an 

 imperceptible gradation, from these verrucose Manopores to those 

 which are smooth, and also to others with a spinous surface. Among 

 the species we may therefore follow out the Madrepore as it loses its 

 distinct calicles, which become reduced to a cluster of ragged points, 

 and finally are obsolete, and the surface smooth ; or in another direc- 

 tion, the points coalescing into minute crests between the cells, or into 

 long lines (rugae) between series of cells; or uniting and forming 

 isolated prominences, which either constitute the interstices, or are 

 scattered over these interstitial spaces. In one species the cells are 

 situated at the bottom of deep circular pits, a peculiarity which we 

 may trace to a coalescence pf the prominences of the interstices around 

 the cells. 



The polyps of the genus have twelve short tentacles, forming a 

 narrow margin to the circular disk in which the mouth is situated ; 

 and in some species they are mere crenations to the disk. They are 

 variously tinted ; lilac, green, and yellow, are some of the colours 

 observed, and the disk is often marked with radiating lines, or series 

 of spots of different shades. 



The species grow, occasionally, to a breadth of eighteen or twenty 

 inches. The name of the genus is derived from the Greek t>-<>s, porous 

 and fragile. 



This group is included by Lamarck and Ehrenberg along with 

 the genus Porites, excepting two or three species, which are placed by 

 the former in the genera Agaricia, Millepora, and Explanaria. Blain- 

 ville is the only author who has formed for any of them a distinct 

 genus; and this Montipora is based upon an unimportant character, 

 the presence of verrucas over the surface (to which his name alludes), 

 and includes only a small part of the Manoporae. 



