MJEANDRINA. 73 



M.EAXDRIXA Lamk. 



Pallas had already pointed out the difference between the meandri- 

 form corals with entire septa (Pectinia) and those with denticulate 

 septa (Maeandrina) ; the former he called Madrepora bd>;/rinl]iiea. the 

 latter Madrepora mceandrites. After him, however, they were placed in 

 the same genus by most of the authors, until Oken finally separated 

 them. Milne-Edwards and Haime subdivided the true Maeandrinae into 

 several genera, though not always very successfully. Thus Manicina 

 and MaBandrina are said to differ by the presence of paliform lobes in 

 the former and their absence in the latter, whilst in reality they are 

 fully as much developed in most of the Maeandrinae as in Manicina. 

 These genera differ only by their mode of growth. 



The genus Coeloria, of the same authors, has been separated from 

 Maeandrina by exceedingly vague characters ; it is not difficult to find 

 parts of the same polypidom which could be made to fit one or the 

 other of these genera. Xo doubt much of the confusion existing in 

 this group is due to a considerable range of variation in the same 

 species, and to the large proportion of worn specimens which have 

 served as types for description. 



I can recognize with tolerable certainty but three species on the coast 

 of Florida. 



Mceandrina labyrinthiformis Oken (Mreandra). 



Madrepora labyrinthijbrmi* (pars) Lns. 

 1/ 'repara lahyrinlhir.a El.I.IS & Sol.. PI. 46, fig* 3 and 4. 

 Mmlrepora maanilriles (pirs) Esi'KR. PI. 4 A. 

 Mceamlrina lah/p-inthica Dan \ 



M -Eow. X IF. Ann Si. X.,t.. :!> Ser., t. XT. p. 204, 1349. 

 '-/v.. M.-i:i>\v. & II. II i -r Nat. rtes Coralliaires, 1857. 



The figures of Ellis and E-per render the identification of this species 

 tolerably certain, although it is probable that two species, one of them 

 from the Red Sea, have been confounded under that name. After the 

 two -hall have been compared and probably separated, the question 

 will arise as to which of the two is to retain the old name. 



Duchassaing and Michelotti have not enumerated it among their 

 West Indian corals. 



It is less common in Florida than the two other species, and is found 

 very little below low-water mark. One specimen, presented to the 

 Museum by Captain W. A. Jones, U. S. E., was taken from a block of 

 concrete at Fort Jefferson. Tortugas, which had been in the water 

 twenty years. It measures a foot in diameter and about four inches in 

 thickness in the most convex part. 



no. iv. 10 



