GENERA, SPECIES, &C. Sp07ig. 8 
of Manaar. Redescribed ; has a remarkably distinct dermal sarcodic 
layer. 
Geodia harretti, Bowerbank : Sollas, (12) p. 247, pis. x.-xii., Kors Fiord, 
Norway. Bowerbank’s description corrected. It has a non-cellular 
cuticle. The main excretory tube is connected with its tributaries by 
openings provided with sphincters. Sphincters also occur between the 
intermarginal cavities — here termed chones — and the subcortical crypts. 
Canal system described in detail. Beneath the epidermis lies a tissue 
resembling vegetable parenchymatous tissue, and termed “ vacuolated 
connective tissue,” or “ dermis.” The central substance, or “ mark,” 
is formed of very indistinct globular cells. Sheath of long spicules 
described. Development of globate spicules traced from groups of 
trichites. The adult globates probably wander from the mark into the 
cortex. 
Caminus and Flacospongia are perhaps Monactinellida which have 
developed balls, according to Schmidt, (9) p. 75. Both occur in 
the district reviewed by the writer. 
Placosjwngia melohesioides, Gray, (1) p. 53. Redescribed. It is more 
nearly allied to the Suheritida than to the Geodina ; it is now recorded 
from the Gulf of Manaar. A var. possessing a spinispirular spicule 
occurs in Central America, &c. 
Tetilla polyura, euplocamus, radiata, referred by Schmidt, (9) p. 73, to 
his new genus Fangophilina . 
Stelletta, a classified list of described species given (12) p. 143. S. 
ogariciformis, Schmidt, = Thenea wallichi, Wright. S., evastrum, geodina, 
intermedia, referred with probability to Geodia. 
Stelletta evastrum, Schmidt, (1) p. 135, pi. vii. figs. 41 & 42, Gulf of 
Manaar and Freemantle, Australia. From structure of disk, it appears 
more nearly allied to Geodia than to Stelletta ; S. diseophora and S. 
mamillaris, Schmidt, also belong to group Geodina, not Stellettina. 
Pach\p']astrella, Schmidt, (1) p. 60, should, perhaps, be grouped with 
Samus, Gray. 
Pacli[y']astrella parasitica, Carter, (1) p. 60; from Gulf of Manaar: 
= Samus. 
Pack [y] astrella connectens, var. Without naviculoid and small tuber- 
culated fusiform spicules, Schmidt, (9) p. 68 ; Grenada. 
Corticium, Schmidt, (9) p. 68, pi. ix. fig. 4. Ancorina, 1. c. p. 69. Stel~ 
letta, p. 70. Tisiplionia, p. 71. Tetilla and Craniella, p. 72. 
Plaldnidce[Plac-'], (11) p. 447. New family of Tetractinellida. Its 
place is in or next to the family Pack [y] astrellidce, Carter, and includes 
the three new genera Plakina, Plakortis, and Plalcinastrella, formed by 
Schulze, and distinguished by the possession of spicules derived from a 
quadri-radiato type, not united by horny matter; the bi-radiate or uni-axial 
forms are twisted or roughened in the middle. In stating his reasons for 
grouping the members of this Family together, Schulze, 1. c. p. 440, says 
that Plakortis, though not possessing the Tetractinellid type of spicule, 
may, nevertheless, be safely inferred to come next to Plakina in the 
series, its canal system and its spiculation being deducible from those of 
that genus. He calls attention to the important principle that family 
1880. [voi.. XVII.] D 5 
