280 
THE VOYAGE OF H.M.S. CHALLENGEE. 
Genus 1. Corticium, 0. Schmidt. 
The mesoderm of the ectosome and hypomere consists of chondrenchyma, which also 
forms the walls of the larger water-canals. The spicules are tetractinose asters and 
heterolophose candelabra. 
Corticium candelabrum, 0. Schmidt. 
Corticium candelabrum, O. Schmidt, Spong. Adriat. Meeres, p. 42, pi. iii. fig. 25, 1862. 
„ „ Kolliker, leones Histiologies, p. 67, 1864. 
,, „ O. Schmidt, Spong. Adriat. Meeres, Suppl., ii. p. 2, pi. i. fig. 2, 1866. 
„ „ F. E.. Schulze, Zeitschr. f. wiss. ZooL, Bd. xxxv. p. 410, pL xxii., 1881. 
Sponge. — Massive, irregularly rounded or nodular, with a smooth surface ; or plate- 
like, flat, thin, in crusting, irregularly lobate, with a more or less smooth or tubercular 
surface ; when very young, up to 1 mm. in diameter, rounded knob-like, attached by the 
flat lower surface of the hypomere. Pores, the simple circular openings of the incurrent 
canals, of various size, up to 0*3 mm. in diameter. Oscule, a slit-like opening in the 
hypomere. Canal-system diplodal, flagellated chambers pear-shaped, 0*045 mm. in 
diameter. The pinnacocytes of the outer surface and the adjacent chondrocytes contain 
pigment granules. 
Spicules . — 1 . Microcalthrops, uniformly strewn through the mesoderm ; actines 
usually curved sigmately, 0*036 to 0*04 mm. in length. 2. Candelabra, the cladi of the 
ecactine spined on the outer convex side, those of the esactines fewer in number and 
smooth, not spined. The candelabra form a single layer beneath the epithelium of the 
exterior and of the larger water-canals. 
Colour. — Light yellow, brown, black, probably dependent on locality. Size, up to 60 
mm. in diameter. 
Habitat. — The Adriatic (0. Schmidt) and Zebu (F. E. Schulze). 
Corticium versatile, 0. Schmidt. 
Coi’ticium versatile, O. Schmidt, Spong. Meerb. Mexico, p. 69, pL ix. fig. 5, 1880. 
Sponge. — Forming crusts. 
Spicules. — Candelabra, actines variously cladose, one frequently acladose. The 
number of cladi borne by each actine varies from two to flve. 
Habitat. — St. Vincent; depth, 95 fathoms. 
Genus 2. Calcabrina,^ n. gen. 
Corticidse containing spinose microrabds, in addition to tetractinose asters or 
candelabra. 
^ A proper name, vide Dante, Inferno, canto xxi. line 118. 
