238 bulletin: museum of comparative zoology. 



spongy, with a papillary upper termination. Reproduction ty septal budding 

 and fission. The calices form short series, with two to four distinct calicinal 

 centres. In many places on the upper surface of the corallum the walls of 

 neighboring series seem fused together, but in more eroded places the walls 

 appear distinct. In the section represented in Plate XXXVIII. Fig. 4, it is 

 distinctly shown that the walls of the series are not fused, but that the coral- 

 lites are joined to each other by their costse. There appears to be some 

 exotheca. 



Three other genera seem closely related to the one here characterized. The 

 first is Stiboria of Etallon. The following is the original description : ^ " Poly- 

 pier massif, dtroitement fixd, en lames peu epaisses; les series d'assez faible 

 longueur; calices doubles, plus ou moins tortueux, separes par un sillon assez 

 etroit, au fond duquel on aper9oit plusieurs series de granulations ; tissu peu 

 compacte. Centres complfetement indistincts, pas de columelle. Les cloisons 

 dent^es seulement prfes du centre ; une epitl^ec^ue." The points of difference 

 are, 1st, the series in Stiboriopsis are not separated by a furrow; 2d, the cal- 

 cinal centres are distinct; 3d, there is a spongy columella, with a papillary 

 upper surface, as stated in the description. 



The genus is also closely related to Symphyllia, Edwards and Haime, and 

 Isophyllia of the same authors ; but both of the genera have the septa strongly 

 spined, whereas Stiboriopsis has simply dentate septa. 



Stiboriopsis jamaicaensis, sp. nov. 



Plate XXXVIII. Figs. 2-4. 



The details already presented need not be repeated. The specimen upon 

 which the genus and species are based is a mass 89 mm. long, 63 ram. wide, and 

 about 45 mm. thick. As the specimen has been subjected to some rolling, it 

 originally was larger. The upper surface is subplane, slightly convex. Soli- 

 tary calices have a diameter of 7 to 9 mm. One series of three calices measures 

 15 mm. long and about 5 mm, wide ; another of four calices is 20 mm. long and 

 5 to 7 mm. wide. The thickness of the walls, with interspace between the series, 

 is from 1 to 2 mm. The series are rather straight, very slightly flexuous. The 

 valleys are not very deep, and are widely open. The septa are only moderately 

 stout and are not greatly crowded. A solitary calice about 8 mm. in diameter 

 has about thirty-six septa, alternately large and small. This would be three 

 complete cycles, witli twelve members of the fourth. This septal arrangement 

 is conmion. The various systems and cycles are not distinctly differentiated. 

 The teeth on the septal margins could be seen on only a few septa, but they 

 are not coarse. Tlie inner terminations of the large se]ita are swollen, and 

 bear paliform teeth. The swollen ends and paliforni lobes make a sort of 



1 Lethea Bruntrutana, 1863, p. 386 ; see Plate LVII. Fig. 1. The date of this 

 work is a little uncertain. The Geological Society of London Catalogue gives it as 

 18G1. 



