ON THE SHETLAND CRUSTACEA, TUNICATA, ETC. 3903 
Isodictya palmata (Ellis & Sol.). Shetland (Fleming and Jameson), and more 
recently in 1864 ( fide Bowerbank). 
infundibuliformis (Linn.). Common on the Haaf in 50-170 fathoms. 
My largest specimen measures 94 inches in diameter across the cup, and 
is about 6 inches high. 
es laciniosa, Bowerbank, n. sp. Sponge sessile, fan-shaped, thin. Surface 
uneven, laciniose, minutely hispid. Oscula and pores inconspicuous. 
Dermal membrane pellucid, spiculous; spicula acuate, long and slender, 
not very numerous; retentive spicula dentato-palmate, equianchorate, 
palm rather exceeding one-third the length of the spicnlum, tooth ter- 
minally truncated, numerous, very minute; and also bicalearated biha- 
mate, hami terminations truncated, numerous, very minute. Skeleton— 
rete very diffuse and open, primary lines with from three to five or six 
spicula in thickness ; secondary lines irregular, mostly unispiculous, oc- 
casionally containing two or three spicula. Spicula acuate, stout and 
large. Internal defensive spicula attenuato-acuate, incipiently spinous, 
minute, few in number. Interstitial membranes spiculous ; tension and 
retentive spicula same as those of the dermal membrane. Colour in 
the dried state light ochreous yellow. Habitat. Shetland, 170 fathoms 
(J. G. Jeffreys, Esq., and Rev. A. M. Norman). Examined in the dry 
state.” 
The type-spccimen is fan-shaped, with several pliciform projecticns. 
It measures 7 inches in height and 10 inches across. ‘The structure 
is so unusually open that the sponge is translucent in every part. It 
is a large and remarkably clegant species, on account of its open nct- 
like structure. It was dredged 20-25 miles N. by W. of Burratirth 
Lighthouse in 1867. 
—— fucorum (Johnston), Abundant between tide-marks on the side of 
‘Halse Hellyer, Burrafirth. 
Barleei, Bow. ‘‘ Haaf Banks, Shetland, Mr. Barlee and Mr. Hum- 
phreys ” (Bowerbank). 
—— fimbriata, Bow. Abundant in one spot some 40 miles east of Whalsey 
Skerries, 1861, also to the north of Unst, 1868. 
Genus Rapuioprrma, Bowerbank, n. g. 
“Skeleton without fibres, composed of an irregular network of polyspi- 
culous fagot-like bundles, the spicula of which are compactly cemented to- 
gether at the middle, but are radiating at their terminations.” 
“ Raphioderma coacervata, Bowerbank, n.sp. Sponge sessile, fan-shaped, 
thick. Surface even, irregularly areolated. Oscula simple, minute, 
numerous, Pores inconspicuous. Dermis reticulate ; rete polyspiculous, 
irregular, very strong and wide. Dermal membrane pellucid, abun- 
dantly spiculous ; tension- spicula attenuato-acerate, long and very slen- 
der, dispersed or loosely fasciculated ; retentive spic ula contort bihamate, 
minute and slender, exceedingly numerous, and‘dentato-palmate equi- 
anchorate, variable in size, few in number, dispersed or congregated in 
circular groups. Skeleton irregular and very ccarse ; rete polyspiculous ; 
spicula subfusiformi-acerate, rather stout and long. Interstitial mem- 
brane spicula same as those of the dermal membrane ; dentato-palmate, 
variable in size, equally dispersed, largest ones occasionally congregated 
in circular groups. Gemmules subspherical, membranous, aspiculous. 
Colour in the dried state cream-white. Habitat. Shetland, 170 fathoms, 
J. G. Jeffreys, Esq. and Rev. A. M. Norman.” (Bowerbank, MS.) 
