GENERA^ SPECIES, &c. 
Spong. 7 
Tetractinellida (Sollas). 
Corticium candelabrum^ Schmidt (14), p. 416, pi. xxii. Recorded by 
Schulze from the Adriatic, Naples, and the islands Cebu and Ponape. 
The colour appears to be dependent to some extent upon locality. The 
hyaline cortical substance is not usually so much developed as represented 
by Schmidt and Kolliker ; it descends into the central substance at cer- 
tain points. The inhalent canal system commences partly by large tubes 
with trumpet-shaped openings, leading from the surface, partly by fine 
canals, leading directly to the superficial ciliated chambers, which lie in 
the opaque substance. The latter are bean-shaped, and measure about 
•045 mm. in diameter: a single inhalent canal enters and a single ex- 
halent one leaves each ; the different exhalent canals unite, and form 
tubes of increasing size, which anastomose freely in the basal hyaline 
substance, opening finally by slit-like vents in the lateral margin or lower 
surface of the Sponge. This condition of the internal cavities appears 
from study of a young specimen to be derived from that of a simple sac 
in the way described [see Zool. Rec. xvii.] in Placina monolopha. The 
ectoderm is composed of a continuous unicellular epithelium, and is con- 
tinued over the internal surface of the inhalent canals. The opacity of 
part of the mesoderm is due to the presence of the ciliated chambers, 
and to small, strongly refractive granules, which occur abundantly 
throughout the ground substance. The ground substance of the tran- 
sparent outer part is refractive and homogeneous, and contains spaces 
which enclose cells. The spicules vary much in the closeness with which 
they are aggregated. The candelabra-spicules are very variable, and 
show forms of transition to the simple quadriradiate, and are probably 
derived from it. The quadriradiates develop each within a single cell. 
The sexes are united in the same individual. The nucleus of the 
mature ovum is generally concealed by abundant yelk-globules. The 
structure of the ovum and sperm-masses, and the earlier stages of the 
development of the former, agree essentially with those observed in 
other Siliceous Sponges. 
A Tetracladine Lithistid fully described and figured, without name, 
by P. M. Duncan, J. L. S. xv. p. 320, pi. xxiv., from 1095 fath. off S.W. 
Coast of Spain, 
Hexactinellida (Scbmidt). 
Aphrocallistes sp. fully described and figured by P. M. Duncan, 
J. L. S. XV. p. 324, pi. XXV., from 1095 fath. off S.W. Coast of Spaiu. 
A form is described by Duncan, (8) p. 175, pi. iii. figs. 4—6, as per- 
haps a Dictyonine Hexactiuellid, attached to dead coral from deep water 
off Portugal. 
Another form is described by the same author, 1. c. p. 176, pi. iii. 
figs. 7-10, from the calix of a coral from the North Atlantic, as a Lissa- 
kine Hexactinellid. 
Ilyalonema^ differing slightly from II. lusitanicum^ obtained by the 
