336 A. E. Verrill—The Bermuda Islands; Coral Reefs. 
Pachychalina elastica, sp. nov. 
Sponge tough and elastic when wet, elastic even when dry, digi- 
tate and somewhat dichotomous, the branches springing from a short, 
stout, compressed stem. Branches 10 to 25™™ in diameter, and 50 to 
75™™ long, nearly round, often swollen distally, sometimes coalescent. 
Oscules large, scattered on the sides. Surface, when dry, conspicu- 
ously areolated when the external net-work is lost. The areole are 
2~3™™ in diameter, deep, subangular, and separated by rather stout 
partitions, often 1-2™™ thick, composed of strong and elastic, rather 
coarsely reticulated fibers, many of those next the surface free at 
the tips, giving the surface a tufted and spongy appearance. Outer 
layer easily detached ; when present, it consists of a rather open 
and regular network of slender fibers, allowing the areole to be 
easily seen through it, with the meshes about .2™™ wide. 
The spicules are slender oxeotes, very acute, often bent, .15 to 
.20™" long. They are multiserial and crowded in the fibers, but well 
covered by spongin. Color, when dried, yellowish brown. Not 
very common on the reefs. 
Pachychalina millepora, sp. nov. Plate xxxvo, fig. 8. 
A delicate irregularly branched sponge, fragile when dry ; surface 
nearly smooth, very finely reticulated; branches irregular in size and 
form, varying from 12 to 25"™ or more in diameter at different 
places. Oscules irregularly scattered on the branches, 2-4™™ in 
diameter, with the edges slightly fringed and little raised; some- 
times funnel-shaped. Dermal layer very finely and pretty regularly 
reticulated. The meshes angular or rounded, with minute points at 
the angles. Areolie, under the cortex, not crowded, separated by 
walls equal in thickness to the diameter of the areole. Fibers about 
.03 to .04™™ thick, filled with abundant multiserial spicules, which are 
rather slender oxeotes, mostly .2 to .22™™ long, often about equal in 
length to the sides of the meshes. 
Pachychalina monticulosa, sp. nov. Plate xxxvp, figs. 6, 7. 
Sponge encrusting, or massive and irregularly lobulate, bearing 
subeonical on mammiform elevations, each having at the summit a 
rather large oscule, 3—5™" in diameter. Internal texture not very 
fine; dermal reticulation formed by small polygonal meshes, visible 
to the naked eye. Subdermal areol rounded, very unequal in size, 
the larger about 1™™ broad, separated by walls usually about as wide, 
made up of irregular and somewhat coarse reticulations, tympanized 
by films of sarcode. Fibers rather coarse, uneven, with numerous 
