336 
THE VOYAGE OF H.M.S. CHALLENGEE. 
ends of the cladi but along tlieir whole length, syzygial laminae growing over the cladus 
as far as tubercles are present. 2. Discotrisene (?). 3. Oxea, fusiform, occasionally 
bearing one or more lateral rounded tubercles, 0‘6 by 0’013 mm. 
II. Microscleres. 4. Microxea, fusiform, slender, centrotylote ; 0’045 mm. in length. 
Colour. — (?). Size, about 20 mm. in height by 5 mm. in diameter. 
Habitat. — Havanna ; depth, 292 fathoms. 
Remarhs. — The protuberances on the sides of the sponge are few in number, from 
one to three, and appear to be spirally arranged ; they give the outline of the sponge an 
undulating zigzag appearance ; thus in a specimen with two protuberances the sponge 
slopes in a straight line to one side as far as the first protuberance, then it bends to the 
other side and proceeds obliquely in a straight line to the next protuberance ; from this 
again it bends to the opposite side, and then continues obliquely in a straight line to the 
summit. All the specimens I have seen are merely skeletons devoid of ectosomal spicules, 
hence the appearance of furrows on the surface, which as Schmidt remarks were naturally 
covered over by a dermal membrane in the living state. No canals of equal diameter to 
that of the furrows are seen at the summit of the sponge or of the lateral protuberances. 
Two specimens were boiled in nitric acid in the expectation of detaching any loose 
spicules which might be present. In this way several lobate discotriaenes hke those of 
Discodermia poly discus were obtained, but these may be foreign inclosures ; the microxeas, 
however, which were thus obtained are so abundant and fresh that I have unhesitatingly 
included them in my description of the spicules proper to the sponge. 
Genus 6. Collinella, 0. Schmidt. 
Generic character partly included in the description of the single species, partly 
unknown. 
Collinella inscripta, 0. Schmidt. 
Collinella inscripta, 0. Schmidt, Spong. Meerb. Mexico, p. 21, pi. i. fig. 3; pi. ii. fig. 12, 1879. 
Sponge. — Pyriform or almost spherical, with a short, somewhat cylindrical pedicle, 
attached by an expanded base. A single oscule at the summit leading into a tubular 
cloaca, which extends axially downwards to the base, or additional smaller oscules are 
present, the additional cloacas running parallel to the main one. Excurrent canals, 
curved, running more or less longitudinally and parallel to the general surface, the most 
superficial exposed as deep branching grooves in deciduous specimens. The general 
surface raised into low monticules, from the summits of which the incurrent canals 
proceed, radiating in all directions, from right angles to the surface to parallelism with 
