250 G. HERBERT FOWLER. 



terial spaces, as it is probable that, since the morphological differences 

 of the whole group of Zoantharia hexacoralla are very slight, such 

 structural variations might be useful for a new classification, which, if 

 based upon the relations of polyp to skeleton, will be on a far sounder 

 foundation than the present one, which rests upon the skeleton alone. 



Flabellum patagonicum (Moseley). 



This is an imperforate Madreporarian, belonging to the family Turbi- 

 nolidae. As Moseley (II) has given a full description of the specific 

 characters of the corallum in his " Challenger " Eeport (to which 

 reference should be made for figures of the complete calyx), only a few 

 of them will be mentioned here. 



i. The corallum is solitary and conical, the apex of the cone forming 

 a pedicle by which the polyp is attached when young; in the adult 

 the pedicle becomes obliterated and the coral free (vide figs. 2, 3, Pe.). 

 The outline of the mouth of the calyx is oval (fig. 1). There are four 

 orders of septa, all of which are entoccelic ; six of the first order, which 

 meet in an elementary form of columella ; six of the second, which are 

 nearly as long as the primary septa ; twelve of the third, and twenty- 

 four of the fourth order. In some specimens the full number is not 

 developed. The corallum is about 2 cm. high in a well-grown specimen ; 

 and the longer axis of the calyx mouth about 2 J cm., the shorter axis 

 2 cm. in length. 



Along the lines which correspond on the exterior surface of the 

 theca with the attachments of the septa on the interior, are shallow 

 but distinct grooves running from lip of calyx to tip of pedicle, each 

 corresponding exactly in position with a septum. These do not agree 

 with v. Koch's views as to the origin of the theca from fusion of the 

 septa, to accord with which costse should be developed in this position, 

 such as occur in many forms. 



The whole of the exterior surface of the theca shows well-marked 

 lines of growth (fig. 4), so arranged as to appear to indicate that the 

 chief centres of activity for the secretion of coral 'lie in the septa. 

 Hence the lip of the calyx is slightly dentate (figs. 3, 4). 



While the upper fourth of the external surface of the theca is, like 

 the whole of the interior of the calyx, glistening, white, and hard, the 

 lower three-fourths are soft in texture and brownish. This latter 

 portion was described by Moseley as a "light-brown epitheca." But 

 on decalcification the brown substance falls off as soft flakes, which, by 



