28 MADEEPOKARIA. 



4. Pontes Cape Verde Islands 3, (P. Insularum Arsinarii tertia.) 



(PL I. fig. 4) 



[St. Vincent, colL Lowe, Eev. R. B. Watson ; Biitish Museum.] 



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

 complete form and method of branching are unknown. 



The calicles 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 project ; these may be thick, rough and echinulate, and of such 

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

 only gradually inwards to join a large columellar tangle. From this granules, minute, uregular 

 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 (a) 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 have been a detached fragment when discovered, for one side has been killed down 

 and the living layer of the upper surface 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 (a) has a lighter network and consequently a more open columellar tangle, and 

 larger pores between the trabeculse in the section than b. In this latter the columellar tangle 

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

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

 region of 6 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 theu' skeletal tips were 

 dying down and being corroded. 



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



