410 
BULLETIN" OF THE UNITED STATES FISH COMMISSION. 
be formed. Diameter of fiber, for the most part, about 500 /<; core 0.6 to 0.8 whole thickness. Sand 
grains scattered sparsely, more abundantly in places, through parenchyma. 
The peculiar character of the skeleton marks off Dendrospongia from the species of Aplysina. The 
interesting similarity between Dendrospongia and the Aplysillidx has been pointed out by Von 
Lendenfeld (1889, p. 424). 
Family SPONGELIDJi F. E. Schulze. 
Flagellated chambers open directly, by means of a wide mouth, into exhalent cavities. Skeletal 
fiber with thin axial core. Fibers in general cored with foreign inclusions. 
Genus SPONGELIA Nardo (1834). 
Flagellated chambers large and sac-shaped. Skeletal libers form an irregular reticulum. Main 
fibers abundantly cored with inclusions; connectives also so cored, or more or less free from inclusions. 
Spongelia pallescens (O. Schmidt) subsp. fragilis var. ramosa, F. E. Schulze. 
Spongelia pallescens, O. Schmidt, 1862, p. 30, Taf. hi, fig. 8. 
Spongelia pallescens subsp. Jragilis var. ramosa, F. E. Schulze, 1879 b, pp. 150, 154, Taf. v-vm. 
Spongelia pallescens, Polejaeff, 1S84, p. 42, pi. in, fig. 1 . 
Spongelia fragilis var. irregularis, Lendenfeld, 1889, p. 662, pi. 37, fig. 10. 
One specimen, “off Punta de Melones.” 
Sponge consists of several upright, digitate (some cylindrical, some flattened) lobes, united at the 
base and here and there fused laterally. Total height of mass, 60 mm.; greatest width, 50 mm. 
Diameter of lobes, 5 to 15 mm. Lobes, with exception of one, solid and without terminal osculum. 
Exceptional lobe tubular, with a terminal osculum 3 mm. diameter leading into an axial cavity. 
Remaining oscula (three) about 3 mm. diameter, and on sides of lobes. Flagellated chambers measure 
60 to 70 ju by 40 to 50 p. Conuli, 1 mm. high, 2 to 3 mm. apart. Consistency fleshy, yielding, and 
somewhat elastic, with sufficient firmness for the sponge lobes perfectly to retain their natural shape 
and position when sponge is removed from the fluid. Color, blackish gray. 
From the conuli radiate band-like ridges, which branch and anastomose so as to form a network, 
in meshes of which lie the pore areas. Only a few of the ridges are supported by skeletal fibers. 
Most contain merely scattered sand grains and spicule fragments, such as are found throughout the 
dermal membrane; also many fibrous cells; also, as a rule, closely packed cords of the commensal alga, 
Oscillaria spongelia i (Schulze, 1879 b, p. 147, Taf. vm, figs. 9, 10). The latter is extremely abundant in 
and just below the dermal membrane, but is nearly absent from the interior. The band-like ridges 
are everywhere distinct to the eye, and in regions where the pores are opened to their widest extent 
they become very obvious. 
Skeleton. — Main longitudinal fibers, 350 p thick, narrowing down in places to diameter of 170 p, 
lie about 2 mm. apart; somewhat fascicular, and densely crowded with sand grains, spicule fragments, 
and foraminifer shells. Main fibers branch at acute angles, branches extending outward and upward 
to terminate in the conuli. Connectives vary in thickness from 100 to 60 p , and also are for the most 
part thickly crowded with inclusions. In some of the smaller fibers, the inclusions are only abundant 
enough to form an axial string. 
The system of connectives is fundamentally ladder-like, giving rise to large squarish meshes, 
each occupying the whole space between a pair of main fibers and having a longitudinal or radial 
length of about 1.5 mm. Connectives separating successive meshes of this sort are occasionally simple, 
but usually branch and form secondary reticula with meshes commonly 300 to 700 p diameter. The 
large squarish meshes, just alluded to, are in places broken up into smaller ones by the branching of 
the connectives. Connectives extending between outer ends of main fibers are in many places, but 
not everywhere, sufficiently branched to give rise to a superficial reticulum with meshes commonly 
400 to 700 p diameter. 
