558 Mr. H. N. Moseley on the true 



StepJianophyllia complicata and S. formosissima. 

 Two species of corals, procured from 126 fathoms in the neighbour- 

 hood of the Ke Islands, have been referred to the genus StepJianophyllia. 

 Both species are discoid, and have their wall extremely perforate ; in 

 fact composed merely of finely trabecular tissue. Two genera of discoid 

 corals, Micrabacia and Stephanophyllia, are given by M.-Edwards and 

 Haime*, which present this peculiarity of having their wall covered with 

 minute perforations, so as to be sieve-like in appearance. The genus 

 Micrabacia is placed amongst the imperforate corals ; whilst Bteplia- 

 nqphyllia is considered one of the Eupsarnmidae. The differences be- 

 tween the two genera seem difficult to define. Both are remarkable for 

 having the costae corresponding in position to the interspaces between 

 the septa, and not to the septa themselves. The present species are 

 placed in the genus Stephanopliyllia, because in one species all the septa, 

 excepting the primary, fuse together before reaching the columella; 

 whilst in the second species a peculiar extreme fusion and contortion of 

 the septa takes place with the advancing age of the coral, which renders 

 it very like Stephanophyllia florealis figured by Quenstedt t. The alter- 

 nation of the costae with the septa, the presence of five cycles of septa, 

 and perforation of the base here occurring are characters common to 

 both genera, Micrabacia and Stephanophyllia. The two species here 

 described are placed provisionally in the genus Stephanophyllia ; a new 

 genus may have to be formed for them. They seem to have little or no 

 affinity to the Eupsaminidae. 



Stephanophyllia complicata, sp. n. 



The corallum is circular, free, and without trace of adherence ; it has 

 the form of a biconvex lens, the base being very slightly curved, and the 

 upper surface greatly so. The under surface, or wall, is perforated by 

 rows of oblong holes arranged in regular series along the interspaces be- 

 tween the costae. The costae are fine ridges covered with small swellings 

 and granules, which radiate out with great regularity from the centre of 

 the basal disk ; they commence in the centre from six very short roots 

 of origin, which immediately bifurcate, thus becoming twelve. The bi- 

 furcation of each of the costal ridges proceeds at successive distances 

 from the centre, until at the margin of the adult coral there are 96 

 costae present, 16 in each system. The costae at the margin of the calicle 

 are slightly grooved, showing a tendency to divide again. The perfora- 

 tions between the costae form about 22 concentrically arranged rows. 

 The coral is very convex above the septal meshwork, rising in an even 

 curve which culminates at the columella. There is scarcely any central 

 fossa. There are six systems of septa and five cycles. The primary- 

 septa are thin straight lamellae with untoothed margins, which proceed 



* M.-Edw. & H. I c. t. iii. pp. 39 & 108. 



t Petrefactenkunde, Taf. lxxvi. no. 12, p. 789; Jura, p. 587. 



