9 S2)on(j. 
SPONQIJDA. 
likeness is not to be sought exclusively in the actual present resemblance 
between forms of spicules, but in the possibility of the two sets of spicules 
being derived from a common stock. Further, the peculiar forms 
assumed by spicules are due not to crystallization, but to conditions con- 
nected with the intimate organization of the soft tissues. In this Family, 
bi-, tri-, and quadri-radiato spicules are seen to form but a single develop 
mental series. The earliest siliceous Sponge-spicules were probably 
many-rayed forms, so that bi-radiate or linear forms are the latest, having 
come through a quadri-radiate stage. 
The Lithcstlidce are the nearest of all the Tetractinellidce to the Ancho- 
rate Sponges ; (9) p. 87. 
Lithistima. Modes of growth of Gulf of Manaar species, (1) p. 142; 
individuals abundant there. 
Collectella avita, Schmidt, (9) p. 86, pi. v. fig. 1, described as new from 
Gulf of Mexico [c/*. Zool. Rec. xvi.]. 
Dactylocalyx pratti^ Bowerbank, = Theonella swinhoeiy Gray ; (1) p. 147. 
Discodermida, (1) p. 145. Growth takes place by transformation of 
surface disks into the complicated spicules of the interior. 
Spongia baicalensis, Pallas, (4) p. 12, pi. i. fig. 1, pi. ii. fig. 5, pi. iii. 
fig. 1, = LuhomirsMa, g. n. The length of the skeleton spicules varies 
in different specimens, from T68 to *243 mm., the maximum diameter 
from *009 to *024 mm. ; the young form of the Sponge is encrusting. 
Four varieties, jS, 7, & 5, are distinguished, pis. i. ii. & iv. figs., differing 
either in the spination or the proportions of the skeleton spicules. 
Veluspa polymorpha, Miklucho-Maclay, (4) p. 36. Is broken up by 
Dybowsky. Var. gracilis — Reniera\ var. baicalensis = Lubomirslda^ 
g. n. ; var. arctica — Fachychalina compressa, Schmidt ; the remaining 8 
varieties, pi. ii. fig. 4, pi. iv. figs. 6, 6, & 10, are described and retained to 
represent the old species ; var. flabelliformis is the typical form. The 
genus Veluspa, as limited by Dybowsky, 1. c., is nearly related to 
Trachya and Clathria. 
Lubomirshia, Dybowsky, (4) p. 11. Characterized as a new genus, but 
see Zool. Rec. xv. The new species of 1878 are fully characterized, viz., 
L. bacillifera, id. p. 22, pi. ii. fig. 1, pi. iv. fig. 2 a, Lake Baikal, chiefly the 
south-west coast ; 3 varieties distinguished, a, j8, 7, pis. i. & iv. various 
figs. ; L. intermedia, id. p. 28, pi. iv. fig. 3, at mouths of rivers flowing 
into Lake Baikal ; one variety, o, distinguished ; L. papyracen, id. p. 33, 
pi. i. fig. 7, pi. iii. fig. 2, pi. iv. fig. 4, southern end of Lake Baikal, at 
slight depths. 
Spongilla. Results of observations on the physiology ; J. Fullagar, 
Sci. Gos. xvi. pp. 3, 11, & 64, figs. 1-3, 65-69. 
Spongilla. A species shortly described from a stream near Philadelphia 
by Potts, P. Ac. Philad. 1880, p. 330, without name ; S.fragilis, Leidy, 
and a sp. n. [infrd^ by the same author. Spongilla stagnalis, Dawson ?, 
Adirondack Lakes, N. America, and another species from a lake, nearly 
allied to S. lacustris; S.fragilis, var. n. minuta, from a cellar in Penn- 
sylvania, tom. cit. p. 357. 
Spongilla baileyi ?, and another doubtful Spongilla described from 
Niagara River, in Am. J. Micr. v. p. 132. 
