168 Dr. J. E. Gray on a new Genus ofEscharidse. 



are necessary to support the extremely fine and brittle cell- 

 structure of the frond. The whole zoophyte can therefore 

 only be dried and preserved with great care ; but if it dies in 

 the sea the calcareous matter soon after death dissolves in the 

 sea-water, and, instead of the stiff light bluish grey-brown 

 zoophyte, one only finds a pale brown, horny, shining skeleton 

 with more transparent cells ; a similar skeleton may be ob- 

 tained by j)lacing a frond in very weak acid. The ribs of the 

 frond are then visible ; and one recognizes on these teeth the 

 points by which the bordering seam is connected with it." 



Dr. Krauss describes both sides of the frond as covered with 

 blunt rhomboidal cells ; " at the upper end of each cell is a 

 rounded, four-cornered, untoothed, oblique oral opening, and 

 on the side of the opening there is a small circular anal 

 aperture. This second opening is always directed sideways 

 towards the edge of the frond ; that is to say, if a perpendicular 

 line is drawn from the middle of the frond, it is found to be on 

 the right side of the line on the right side, and on the left of 

 it on the left side of the oral aperture. Immediately below 

 the oral aperture is to be observed a second, very small opening, 

 the use of which is not known." Similar openings are to be 

 seen in several species of Lepralia. 



It is curious that Dr. Krauss, who observes so accurately 

 the structure of the cell, did not see that the coralline was 

 much more closely allied to Eschara and Lepralia than to 

 Flustra. 



The other species is perhaps described by Mr. Busk as 

 Eschara ; but he does not mention the margin or divisions. 



Fam. Escharidae. 

 Genus Flustramorpha. 



Polyzoarium frondose, flabellate, furcately divided ; cells 

 disposed on both surfaces back to back, immersed, coalescent, 

 parallel to the plane of the axis. Oral opening with a small 

 tubular opening on one side of it and a smaller aperture be- 

 neath. The frond supported by cylindrical horny fibres, Avhich 

 traverse it in various directions and edge the two margins 

 of the lobes. 



1. Flustramorpha marcjinata. B.M. 



The polyzoarium grey-brown, rather thin ; the stem and 

 branches strap-shaped, with nearly parallel sides, regularly 

 furcately branched, and margined with a thickened rib. 



Flustra marginata, Krausa, Beitr. Corall, und Zooph. der Siidsee, 1837| 

 p. 35, tab. 1. iigs. 3 a~d. 



Hah. Port Natal. 



