98 MAUREPORARIA. 



partly encrusts the surface of P. West Indies x. 25, and is partly free except that it rests upon a 

 Serpvda tube. The first forking seems to have taken place about 1 cm. above the base, and one 

 of the prongs has since forked three times and always at very short distances, so that branchlets 

 1 cm. thick are reached at about 5 cm. from the base. The living layer of this short, squatly 

 branching corallum extended over the whole, even curling round under the basal disk. 



The calicles are about 2 mm. in diameter and shallow, but with distinct depressions which 

 in the younger calicles are subcircular with a central boss rising in their bases. The walls are 

 flat-topped and about ' 5 mm. thick, and the surface layer is a very delicate filigree of thin 

 threads either as a zigzag or as an angular network, the free ends having frosted knobs. This 

 smooth filigree is quite at the surface and can be seen rising from a much thicker, coarser 

 network immediately below. The septa belong, for the most part, to this stouter lower layer ; 

 they are short, free, irregular, and their tips end in larger frosted knobs of the same kind. 

 They seem even to thicken and become coarser as they descend further into the calicle. 



From the confused tissue filling up the base of the fossa, in which the septa lose 

 themselves, pali arise as a small, compact, irregular ring of four to five frosted points. There is 

 a smaller central tubercle in the younger calicles, but in the older the pali have that peculiar 

 rosette-Kke appearance shown in Milne-Edwards' figure of P. furcata, which was intended to 

 illustrate the structure of Porites* The small frosted tip of the palus is surrounded by a frill 

 of delicate tissue like a collar, and is either an indication of the sudden thickening of the whole 

 palus, or the outgrowth of somewhat flaky, horizontal, skeletal matter. The edges of the septa 

 show the same horizontal fringes. 



The section shows a very open loose reticulum, in which the trabeculse are somewhat 

 pronounced, being thick, nodulated, and separated by large round pores ; tlie horizontal 

 elements are also well developed, but less so than the trabeculse. 



Here, again, is a branching Porites which differs very decidedly from any other in the 

 National Collection. It has one character, namely, the frilling round the pali, somewhat like 

 that of Milne-Edwards' figure above cited, and which was so unintelligible to me in that 

 drawing as for long to discount its value to my mind. But this specimen shows it. On the 

 other hand, the peculiar texture of the walls and the growth-forms are quite different from 

 those shown in Milne-Edwards' figure. It is especially to be regretted that there is no recorded 

 locality for this specimen, which grew upon an old beer bottle, and is here placed among the 

 West Indian forms because of the character of its skeleton, and also because it grows upon an 

 encrusting form (P. West Indies x. 25), which also has the West Indian type of Pontes 

 skeleton, see below, p. 102. 



It is to be noted that the Serpula, upon whose tube the basal disk partly rested, became 

 involved in the coral. It and its tube grew up with the ascending stock. Perhaps it is to the 

 stimulation of this organism that we must attribute the fact that one of the two prongs 

 resulting from the first forking, namely, that one in which the worm-tube ran, grew more 

 rapidly than the other. The bottle, on which it was growing, is of an antiquated type. 



a. Zool. Dept. 1903. 7. 31. 1. 



• Ann. Sci. Nat. (3°) xvi. pi. i. fig. la. 



