28 MADKEPORARIA. 



4, Porites Cape Verde Islands 3, (P. Imularum Ardnarii tertia.) 

 (I'l. I. fig. 4) 



[St. Vincent, coll. T.owe, Rev. E. B. Watson ; British Museum.] 



Description. — The corallum rises into stout irregular stems, 2 cm. aud more thick ; the 

 complete form and method of branching are unknown. 



The caliclcs are deep and conspicuous, varying from 1 ■ 5 to 2 mm. in diameter ; smallest 

 and deepest near the tips. The walls are irregularly zigzag threads from the angles of which 

 short, irregular septal rods jjrojcct ; these may be thick, rough and ecliinulate, and of such 

 different lengths that some few of them meet and fuse high up, while the majority slope 

 only gradvuilly inwards to join a large columellar tangle. From this granules, minute, irregular 

 and only showing traces of the typical formula, arise and represent pali and a central tubercle. 



The vertical section shows stout, very irregular, and inconspicuous trabeculse, with rows 

 of round pores between. These pores are large or small according to the degree of compact- 

 ness of the skeleton, which is naturally strongest and most solid near the base. 



There are two fragments. One («) the tip of a broad stem, 3 cm. long, and flattened as if 

 about to divide up into 3 prongs. The other (6) is an irregular stem, about 8 cm. long, which 

 seems to liave been a detached fragmimt when discovered, for one side has been killed down 

 and the living layer of the upper suiface tends to creep down on each side over the dead 

 portion. Both fragments have the same kind of calicle with large deep circular fossa, but 

 the smaller («) has a lighter network and consequently a more open columellar tangle, and 

 larger pores between the trabecule in the section than h. In this latter the columellar tangle 

 appears nearly solid, and the pores in the section are very small ; the short nodulated trabeculaj 

 fusing together render the section of the older part nearly solid. The surface of the basal 

 region of h is somewhat remarkable, for, seen sideways, the trabecular elements tend to rise 

 as such above the surface, many of them with round knobs, as if their skeletal tips were 

 dying down and being coiToded. 



a and b. Fragments in a box together. Zool. Dept. 79. 5. 28. 22. 



