WEST INDIAN ISLANDS PORITES. 41 



In addition to the above is another complete brancli, labelled simply " Barbados," which 

 may have been of the same kind. It is much bent, and covered with mammillate processes. 

 But the character which suggests affinity most strongly is the fact that the calicles have no 

 clearly defined walls near the tips. This, coupled with the general similarity in size and growth- 

 form, as far as the latter can be made out in a, justifies us in provisionally classing them 

 together, in spite of such differences as the slightly greater size of the calicles and the compara- 

 tive openness of the skeletal network in this specimen. 



c. PI. IX. fig. 3, left-hand figure. Geol. Dept. R. 2489. 



19. Porites Barbados 9. {P. liarhatcv. nona.) 



[High level reef, Castle Grant, coll. Jukes Browne ; and summit of Mount Misery, 1053 feet, 

 St. Thomas Parish, coll. Colonel Fielden (Pleistocene) ; British Museum.] 



Under this heading three massive fragments, which seem to be of the same kind, are 

 included. The coral seems to have spread as thick flat cakes with very wavy surface, indeed 

 mounting into a number of domelike uprisings (specimens a and h) with deep, narrow, round- 

 bottomed depressions between (specimen a). These domes were of different sizes and heights, 

 large (up to 2 • 5 cm.) and small. This is a specialisation of the surface not elsewhere known 

 among the astrseoid Porites. 



The coral (specimen «), during fossilisation, has decayed in such a manner as to appear to 

 have been built up of tier upon tier of thin layers, which, in the section, can be seen to curve 

 up and down over the domes and into the valleys. These are probably lines of weakness due 

 to the hollowing out of some of the thick horizontal layers of the skeleton by boring algse. 



In the sections (specimens a. and h) the elements, vertical and horizontal, are both con- 

 spicuous, not so thick, perhaps, as in the fossil massive form P. Trinidad 1 (see PI. I. 

 fig. 5, 6), and certainly not so conspicuously beaded. One remarkable point is the presence of 

 very large smooth rods (in specimen a) running always parallel with, and looking as if they 

 were, very large trabeculae, but unlike trabecule in being attached only at a few points to 

 the rest of the skeleton ; these appear at the surface as small, open rings. I take them to 

 represent the remains of worm-tubes, which retain the same thickness through the coral. 

 Appearances suggest that these were numerous in the deep valleys, but not always present on 

 the domelike uprisings. In this connection we may note also that the elements of the dome- 

 like elevations are not so thick and pronounced, the skeleton having altogether a lighter and 

 more irregularly reticular texture than in the depressions. 



Specimen c, which seems to be from the same locality as specimen a, shows these thick 

 trabeculae or worm-tubes rather more closely joined to the skeleton, but still individualised in 

 a way which seems to distinguish them from trabeculae, unless they might be some very 

 special development of the central columellar tubercle ; but if that were the case, some radial 

 symmetry should be seen round them, which is hardly ever the case. Indeed they are at 

 times found crowded together. 



o 



