A. E. Verril—The Bermuda Islands; Coral Reefs. 309 
interior of the caeenenchyma, near the axis, is usually purple, due to 
the internal fusiform purple spicules. 
This is most common on the outer reefs in 10 to 20 feet of water, 
where it grows to great size, but it is also common on the inner reefs 
and ledges, where specimens 2 to 3 feet high are often found. It is 
a common species in the West Indies and on the Florida Reefs. 
Plexauropsis, gen. nov. 
Axis and spicula similar to those of Plexaura. Polyps wholly 
retractile, nearly destitute of spicula both in the column and ten- 
tacles. Ccanenchyma rather thick, with a cortical layer of small 
spinose or foliated clubs, and sometimes with one-sided, irregular, 
spinose forms, giving a finely granular appearance to the surface 
under a lens. Calicles wholly immersed or with the borders only 
slightly raised and unarmed. 
Plexauropsis bicolor, sp. nov. Figure 149. Plate xxxiiis, figs. 2, b, ¢, 
spicules. Plate xxxvia, figs. 1, 2, spicules. 
Colony dichotomously branched, a foot or more high (300™™), with 
the terminal twigs 4 to 6™™ in diameter and 75 to 125™™ long, terete, 
little tapered, obtuse at tips. Calicles nearly round, about .5™™" in 
diameter, arranged somewhat in quincunx, rather close together, 
the intervals often about equal to their diameters, often more 
crowded distally, and more separated on the larger branches. 
Polyps much exsert (see plate), translucent, pale brownish yellow; 
tentacles lanceolate, a little obtuse, with about seven or eight close 
obtuse pinne on each side. The polyps contract only very slowly 
and seldom completely when disturbed, so that they are easily pre- 
served fully extended in formol. 
The cceenenchyma is relatively thick, dark purple within, but with 
a thin cortical layer of pale yellow or whitish spicules (hence the 
name). he cortical spicules are mostly rough, subfoliated and spi- 
nose minute clubs, of various sizes and forms, but mixed with many 
irregular and one-sided spindles and oblong forms, with the outer 
edge roughly spinose or thorny, much as on the distal end of the clubs. 
The purple spicules of the cenenchyma are mostly elongated, rather 
slender, acute spindles of various small sizes, with the verruce small 
and not much crowded; a few are branched and there are a few 
shorter and thicker acute spindles, enlarged in the middle. . 
Taken in shallow water in 1901. 
