118 A. E. Verrill — Bermudian and West Indian Reef Corals. 



genus. The infolding of the margin is often delayed till the calicle 

 is 25 to 40""" across. 



But frequently the first outfoldings of the margin begin much 

 sooner than usual to form secondary folds of the same nature, before 

 the first series of calicles is fully formed. This gives rise to the 

 early formation of a much larger number of calicles, some of which 

 may long remain incomplete and united in series. For the same 

 reason the calicles in such a coral will be, for some time, smaller in 

 size than those that divide more slowly, thus giving them a very 

 different appearance. But both conditions ma}^ exist at the same 

 time on some specimens, and many irregularities constantly occur. 

 (See pi. xvii, figs. 5, 6.) Some species, however, normally divide 

 more rapidly than others. (PL xx, fig. 1.) The outfoldings of the 

 margin may not much affect its regular circular outline, as in pi. 

 xvii, figs. 1, 2, {I. frag His). But in other cases they may be so 

 extensive as to produce a deeply lobulated outline, when seen from 

 below, as in pi. xvii, fig. 3, (Z fragilis). Large specimens of either 

 species (see pi. xvii, figs. 5, G of fragilis) generally have a large 

 number of calicles, irregularly arranged, many of them isolated, but 

 mostly in short series. 



Resorption of parts of the walls and septa or of the entire thick- 

 ness of the collines frequently takes place, and thus alters the appear- 

 ance. In some cases this results in breaking up the collines into 

 detached portions or isolated columns. This I have seen in I. fragilis. 



The genus is chiefly, or perhaps entirelj^, American. The simple 

 form described as I. australis, first from Austi"alia, was considered 

 the tyjDC of a special genus, IlomophylUa, by Bruggmann, 1877. 

 The species described by Klunzinger from the Red Sea as /. ery- 

 thrma appears to me to belong rather to Ulophyllia or Mussa. 



Isophyllia dipsacea Daua. Eose Coral. 



Mifssrt dipsacea Dana, Zooph., p. 184, 1846. 



Symjjhi/llia dipsacea Edw. and Haime, CoralL, ii, p. 373, 1857. 

 Isophyllia dipsacea Verrill, Bull. Mns. Comp. Zool., i, p. 49, 1864 ; Pourtales, 



Deep Sea Corals, p. 71, 1871 ; Florida Eeefs, pi. vii, figs. 1-8, 1880. 

 Isophyllia australis (pars) Edw. and Haime, CoralL, ii, p. 375 (young), 1857. 

 ? Symphyllia anmnone + S. comferta + S. aglce+S. helianthus + S. Thomasiana + 



S. asp)era + S. cylindrica + /S. Knoxi + S. verrucosa (abnormal) Ducli. and 



Mich., Corall. Antill., pp. 71, 72, 1860. 

 ? Lithophyllia argemone + L. cylindrica Duch. and Mich., op. cit., p. 68, pi. ix^ 



fig. 121, pi. X, fig. 15, pi. ix, figs. 17, 18, 1860, (young). 

 Isophyllia australis + cylindrica + Knoxi + Lithophyllia Cubensis + L. lacera 



{non Pallas) 4- -L. argemone Quelch, Voy. Chall., Zool., xvi, pp. 10, 11, 12, 



pp. 83-86, 1886. 



