WEST INDIAN ISLANDS PORITES. ^1 



edges, denticulate down their axial margins ; without pali, and with a porous columellar tangle 

 composed of slightly twisted lamellae. 



The living colony is brown or purplish-brown ; the tentacles are sometimes a beautiful 

 green, at others a greenish-white. 



This coral again appears to have shown quite definable variations on the ordinary 

 astrffioid type, variations which require recording. The name " Icevigata " refers either to the 

 smoothness of the whole stock or to that of the septa and skeletal elements. This latter 

 smoothness is brought out in tlie original figure No. 16 (printed on the plate as 12) 



The very fact that the authors took this to represent even a new genus, shows tliat it 

 differed very decidedly from both P. St. Thomas 5 and 6. These differences, so emphatically 

 recorded, require to be further investigated, and not ignored as they are by the wholesale 

 lumping of them all together as P. astrceoidcs. 



For another somewhat remarkable form, the P. macrocephala D. and M., which probably 

 comes from this locality, see below, p. 89. 



46. Porites Porto Rico 1. (P. Porti-Riconis p-ima.) (PI. XI. fig. 3.) 

 [Porto Rico, coll. Duchassaing ; Paris Museum.] 



Deseriptioyi.-The corallum rises in rather tall, close and compact tufts. The branches 

 forkdichotomously, about 1-25 cm. apart, and at angles of about 60°. The prong fuithest 

 from the axis of the stock tends usually to bend inwards so as to keep the cluster compact. 

 The stems are somewhat slender, between 1 and 2 cm. ; the terminals are thick and blunt, and 

 the living layer is 4 cm. deep. 



The calicles are large, 1-75 mm., superficial, as dark spots on a loose, open, granular 

 surface The wall-tlireads are excessively thin, mostly wanting. The septa are symmetrical, 

 lono- commencing on the wall as remarkable stellate granules, the septa themselves being 

 laterally so echinulate as to appear feathered. The pali rise as similar stellate granules, usually 

 five, but with others occasionally present. The interseptal loculi are symmetrical ; the colu- 

 mellar tangle is well developed, and the central tubercle flattened. 



This description is based upon my notes on specimen Z 187 / in the Paris Museum, 

 labelled " Porites furcata, Porto Rico, M. Duchassaing." The most remarkable featm-e is the 

 extraordinary development of the echinulation of the skeletal elements. It was quite unique 

 amon- the Paris specimens, and has no close counterpart in any specimen in the liritish 

 Museum As far as I can see, therefore, we have nothing to do with speculations as to 

 whether the specimen is or is not specifically identical with that originally called P. furcata 

 (see p 82). We have to record the forms assumed by the genus. 



In Duchassaing's and Michelotti's Mem. sur les Cor. des Antilles, Suppl. (1864) p. 95, 

 they mention the species Porites furcata Lmk., giving Lesueur's Porites recta (= P. St. Bar- 

 tholomeiv 1) as synonym, but it does not appear to refer to any definite specimen. They merely 

 add that P. furcata occurs in many of the islands of the Caribbean Sea with many variations 

 of form and coloration. 



