SPONQIIDA. 
1 7 S]Jong. 
Plakinastrella[^Plac-'], F. E. Schulze, (11) p. 449. Based on P. copiosa^ 
id. 1. c., pp. 433, & 449, pi. xxi. figs. 17-21, Naples. Dome-shaped, with 
single osculum. Subdermal cavities fairly developed, marking off a 
dermis containing biradiate spicula set at right angles to surface. No 
basal lacuna). Exhalant and inhalant canal-system arborescent and well- 
developed. Spicula of three sizes, viz., large quadri-, tri-, and bi-radiate, 
the two former anchor-shaped when in the dermis. Those of the middle 
size are only quadri- and tri-radiate ; the smallest, chiefly dermal, belong 
to all three forms. The largest alone have visible axial canals. The bi- 
radiates resemble those of Plakina. Ciliated chambers surrounded by 
Corallistes aculeata^ Carter, (1) p. 143, pi. vii. fig. 45, Gulf of Manaar 
and off’ South of Japan. C. verrucosa and C. elegantissima, id. 1. c. p. 144, 
pi. vii. figs. 46 & 47, Gulf of Manaar. 
Discodermia dissoluta, Schmidt, (9) p. 87, pi. v. fig. 2, Barbadoes, 
66 fath. 
Discodermia papillata, Carter, (1) p. 146, pi. viii. fig. 48 ; D. aspera, id. 
1. c. p. 147, pi. viii. fig. 49 ; D. spinispivulifera^ id. 1. c. p 148, pi. viii. 
fig. 50 ; D. Icevidiscus, id. 1. c. p. 149, pi. viii. fig. 51 : all from Gulf of 
Manaar. 
Neopelta, Schmidt, (9) p. 88. Tetracladine. Characterized by the pos- 
session “of uni- axial discs; these appear to be developed from uni-axial 
surface spicules which have assumed this form owing to their position. 
Irregular branching but uni-axial spicules, small fusiform, longer acerate, 
and cylindrical spicules are also present. N. imperfecta^ id. ibid. pi. in. 
fig. 11, Barbadoes, 103 fath. ; N. perfecta, id. ibid. pi. v. fig. 3. 
Azorica cribrophora, Schmidt, (9) p. 89, pi. v. fig. 4, Barbadoes, 200 
fath. 
Spongilla tentasperma, Potts, P. Ac. Philad. 1880, p. 330, stream near 
Philadelphia. Walls of foramen of gemrnule prolonged into tendril- 
like processes. Name altered by the author, tom. cit. p. 357, to teno- 
sperma. 
Spongilla aspinosa, id. tom. cit, p. 357, swamp. New Jersey, S. argyro- 
sperma^ repens, astrosperma, id. ibid., cellar in Pennsylvania. 
Hexactinellida. 
Cystispongia superstes, Schmidt, (9) p. 50, pi. iii. fig. 10, pi. iv. fig. 4, 
pi. vii. fig. 6, Yucatan, Martinique, Morro Light, 20-292 fath. Referred 
to Romer’s Cretaceous genus. 
Dactylocalyx potatorum, Schmidt, (9) p. 53, St. Lucia Island, 151 fath. 
Margaritella, Schmidt, (9) p. 54. Based ou M. cceloptychoides, \di. ibid. 
pi. vii. fig. 7, Havannah, 160 fath. Intermediate between Dactylocalyx 
and Cceloptychium ; no lantern-nodes. 
Joannella, Schmidt, (9) p. 55. Based on J. compressa, id. ibid. pi. iv. 
fig. 11, Gulf of Mexico, off Cuba, 287 fath. Shaped like an open cup, 
skeleton very solid, meshes very narrow ; two forms of rosette, one, being 
a new form, to be called “ knob-rosette.” 
Scleroplegma, Schmidt, (9) p. 56. Cylindrical or conical, with body- 
cavity ; meshes wide, varying from cubical to polyhedric form. S. 
granules. 
