REPORT ON THE TETRACTINELLIDA. 
195 
considerable width, from 3 to 4 mm., and expanding beneath the cortex, open by oscules 
much smaller than themselves, from 1 to 2 mm. in diameter. 
Stryphnus unguiculus, Sollas (PI. XV. figs. 33-39). 
Stryphnus unguiculus, Sollas, Prelim. Account, Sci. Proc. Roy. Dubl. Soc., vol. v. p. 193, 1886. 
Sponge. — Compound, massive, spreading horizontally into irregular lobes, and rising 
into mound-like eminences ; base torn, but apparently free ; oscules evident in groups at 
the ends of the lobes or on the summits of the mounds ; excurrent canals large, running 
longitudinally through the lobes, expanding beneath the oscules, and opening into them 
by chones, of which there are several to each canal. Pores generally distributed. 
Spicules. — I. Megascleres. 1. Somal oxea (PI. XV, fig. 33), fusiform, usually curved, 
variously but usually obtusely pointed, 2'68 by 0'095 mm, 
2. Ectosomal oxea, hispidating the surface, fusiform, much attenuated towards the ends 
as though to terminate in a sharp point, but usually rounded off, 5712 by 0'087 mm. 
3, Dichotriasjie (PI, XV. figs, 34, 35), rhabdome conical, obtusely pointed or rounded 
off at the end ; protocladi projecting only slightly forwards ; deuterocladi directed 
backwards, and after diverging from each other in the usual manner approximating 
so as to become parallel for the latter half of their course. Ehabdome 0'508 by 
0‘0316 mm., protocladi 0‘0276 mm., deuterocladi 0'0395 mm. long, chord of deuterocladi 
0‘0237 mm. 
II. Microscleres. 4. Somal ampTiiaster, typical form as in Stryphnus niger; but 
varieties are, if possible, more numerous. 
5, Choanosomal oxyaster, a small centrum, and sharp, conical, smooth or roughened 
actines, which, though usually numerous, are frequently reduced to six, five, four, three, 
two, or even one in number. A single actine 0'0197 mm. long. 
Colour. — Deep brown externally, dark grey within. 
Habitat. — Port Elizabeth, South Africa (according to the dealer from whom it was 
purchased). 
Remarks. — This species is very similar to Stryphnus niger ; it is distinguished by the 
claw-like cladi of the dichotrieene. 
Subfamily 4. Rhabdasterina. 
Genus 15. Eeionema, Bowerbank. 
Rhabdastrose Stellettidse in which the ectosome does not form a cortex, with two forms 
of microscleres, one of them being a microrabd, derived either from an anthaster or a 
, chiaster by reduction in the number of the actines to two. 
