REPOKT ON THE TETRACTINELLIDA. 
337 
it ; the most superficial or subdermal canals revealed as deep grooves in deciduous 
specimens. 
Habitat. — Morro Light ; depth, 292 fathoms. 
Remarks. — The specimen of this sponge, which I received from Professor Agassiz, is 
smaller than any of those figured by Schmidt, about 15 mm. in diameter, by 18 mm. in 
height. It is entirely devoid of soft parts and loose spicules ; the desmas are compara- 
tively small, an epactine from the actinal centre to zygosis measured 0’039 by 0'019 mm. ; 
the cladi are richly tuberculated, and the syzygial lamina extend over them for consider- 
able distances, sometimes nearly to the actinal centre. 
Genus 7. Sulcastrella, 0. Schmidt, 
Generic character partly included in the description of the single species, partly not 
known. 
Sulcastrella clausa, 0. Schmidt. 
Sulcastrella clausa, 0. Schmidt, Spong. Meerb. Mexico, p. 27, pi. i. fig. 5 ; pi. ii. fig. 6 ; 
pi. iii. fig. 7, 1879. 
Sponge. — Incrusting, oscules absent, pores numerous ; surface raised into low convex 
areas, each of which is occupied by a stellate system of anastomosing subdermal canals 
radiating from the centre. 
Sp>icules.—1. Megascleres, 1. Desma, triradiate, with a triradiate axial fibre, 
distinguished by peculiar finger-like or claw-like processes, syzygial processes not unfre- 
quently surrounded by undulating collar-like processes. 
2. Strongyle, slender. 
II. Microscleres (?). 
Habitat. — Sand Key, Gulf of Mexico; depth, 129 fathoms. 
Remarks. — I have not seen this sponge, which Schmidt places with the Ehizomorina, 
and compares to the fossil Astrobolia, Zittel ; but it appears to me, at least superficially, 
more closely to resemble Spongodiscus, Zittel, which is a Tetracladine Lithistid, as I think 
is the sponge under consideration. 
(ZOOL. CHALL. EXP. — PART LXIII. — 1887.) 
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