CORALS OF THE LONDON CLAY. 33 



systems are apparently double, so that the septal apparatus is divided into eight nearly 

 equal groups. Styloccenia Lapeyrousiana differs from it by its conical form, and by the 

 existence of three complete cycla of septa. Stylocce?iia Taurinensis has equally but two 

 septal cycla, but the mural processes are much smaller than in S. monticularia ; the calices 

 are larger, and the primary septa are united to columella very high up. 



Styloccenia uonticularia has been found at Bracklesham Bay, by Mr. Frederick Edwards, 

 but appears to be rare in that locality ; it is, on the contrary, very common at Grignon, 

 and in many other places near Paris. 



2. Genus Astrocoznia (p. xxx). 



Astrocosnia pulchella. Tab. V, figs. 3, 3 a, 3 b, 3 c. 



Corallum composite, astreiform, massive, or subcolumnar, and presenting at its under 

 surface a common plate, covered with a complete epitheca, delicately wrinkled by concentric 

 striae. Corallites approximating more or less, according to the age of the Coral and the 

 degree of activity with which gemmation has been carried on. When the corallites are 

 not crowded together, the calices are circular, and have a distinct though not prominent 

 edge ; they are also separated by a pseudo-coenenchyma, the surface of which is covered 

 with small costal ridges, that are usually denticulated, so as to assume the appearance of 

 rows of round, obtuse granulae (fig. 3c). When the calices approximate, they become 

 somewhat polygonal, and their margins are separated only by a narrow furrow, or united 

 so as to appear simple. The calicular fossula is very shallow. Columella cylindrical, 

 obtuse, and free to a considerable extent, but not rising quite so high as the septa. Three 

 complete cycla of septa, and six equally- developed systems ; the septa of unequal size, 

 according to their relative age, straight, slightly exsert, closely set, feebly granulated, rather 

 thick externally, and having their upper edge entire and convex. Breadth of the calices, 

 two thirds or three quarters of a line. 



This species belongs to the division of the irregular Astroccenia, 1 for independently of 

 the slight inequality perceptible in the size of the calices, it is evident that gemmation takes 

 place in this Coral simultaneously at various parts ; but it differs from the other species of 

 the same section, by the number of the septa ; here, as we have already said, the six systems 

 are equally developed, whereas in Astroccenia Koninckii, A. Orbignyana, A. reticulata, 

 A. ornata, A. ramosa, and A. decaphylla, there is always apparently eight or even ten 

 systems. 



We know of only three small specimens of this species, which were found at Bracklesham 

 Bay, and belong to the cabinet of Mr. Frederick Edwards. 



1 See our Monograph of the Astreidae, Ann. des Sc. Nat., 3 me serie, vol. x. 



