1863.] DUNCAN WEST INDIAN CORALS. 445 



superior margin irregularly dentate. Each septum corresponds 

 with a costa, is large at the wall, tolerably thick internally, and 

 not delicate in any part of its course. Laminae not granular, well 

 developed, not perforated, joining the columella by delicate processes 

 which pass upwards and inwards. In six systems of three cycles. 

 The primary and secondary septa are nearly equal, and reach the 

 columella ; the tertiary reach but a little way inwards, and end in 

 a sharp edge. Columella parietal, slightly developed. Exotheca 

 tolerably well developed between the costse ; cells nearly square and 

 very small. Endotheca very scanty. Wall cylindrical, well deve- 

 loped. Diameter of the calices -^ inch. 



The fossilization of this specimen is peculiar ; the loculi are not 

 filled with any mineral, and the sclerenchyma is silicified and very 

 crisp in its texture. 



This species is closely allied to the recent Astrcea annularis 

 (Pacific?), but differs in not being convex and subgibbous in shape, 

 in not having a strong paliform tooth on the septa, and in not pre- 

 senting delicate walls and horizontal processes from the laminae 

 to the columella. It is more remote from a common West Indian 

 form (Astrcea stellulata) than it is from A. annularis. 



There is no recent Coral which corresponds to this tall, subplane, 

 simply laminar Astraean. 



Erom the Marl ; the specimen was obtained from a well 40 feet 

 deep. Coll. Geol. Soc, 



A cast has also been obtained from the Marl-formation of Antigua. 



2. OcULTNA, Sp. 



A worn specimen ; species not to be determined. Coll. Geol. Soc. 



3. Madrepora, sp. 



A rolled specimen. Coll. Geol. Soc. 



These last two specimens are too fragmentary for specific determi- 

 nation, and their original position with regard to the raised reef is 

 uncertain. 



D. General Observations on the Genera and Species. 

 I. Antigua. 



The absence of simple Corals from the collection from Antigua is 

 somewhat remarkable, especially when their prevalence in San Do- 

 mingo and Jamaica is considered. Equally remarkable is the 

 presence of no less than nine species of Astrcea, some of them second 

 to none in size and development. The large blocks of these Astrcecz, 

 the existence of Mceandrince, Alveoporce, and a species of Stepha- 

 noccenia, together with a large Rhodarcea, indicate a reef with 

 " Pacific " rather than West Indian peculiarities. 



The predominance of the genus Astrcea is remarkable, and there 

 is no instance of so many forms being found elsewhere in so small an 

 area. The majority of the specimens from Antigua are great masses 

 of Coral covered with casts of the calices, and are for the most 



