ON THE SHETLAND CRUSTACEA, TUNICATA, ETC. 329 



necting spicula expando-ternate ; radii attenuated, very long, shafts 

 very short. Skeleton fasciculi and reticulations stout and polyspicu- 

 lous ; rete open and irregular ; spicula subfusiformi-acerate, long and 

 large. Interstitial membranes pellucid, furnished abundantly with small 

 subfusiformi-acerate tension- spicula, and with numerous large and small 

 attenuate -stellate retentive spicula. Gremmules membranous, aspiculous. 

 Colour in the dried state light grey. Habitat. Shetland, 110 fathoms 

 (Rev. A. M. Norman). Examined in the dried state." 



To this description of Dr. Bowerbank I may add that the " subfusi- 

 formi-acerate tension-spicula " are Jncipiently and entirely spined, and 

 are, moreover, very frequently furnished with a central umbo. 

 Ecionemia compressa, Bow. Rare, in very deep water, Unst Haaf, in 1864 

 and 1868. 



Genus QTJASILLIKA*, Norman, n. g. 



Sponge consisting of a single clavate hollow body, widening upwards from 

 the base, and rising at once from the surface of the stone to which it is at- 

 tached, without any expanded basal mass. Skeleton beautifully reticulate, 

 primary fasciculi ascending in parallel straight lines from the base, and in 

 diverging radiating lines from a central mammaeform projection at the 

 summit of the sponge; secondary fasciculi at right angles to the primary 

 ones. Spicula fusiformi-acuate. 



Qaasillina brevis (Bow. )= Poly mastia brevis, Bow. Brit. Spongiadae, vol. ii. 

 p. 64. Frequent on pebbles in from 40 to 170 fathoms. It is necessary 

 to separate this species from the genus Polymastia ; for whereas in the 

 latter genus several (often very numerous) nstular cloacae arise from an 

 expanded basal mass, which is, in fact, the body of the sponge, in Quasil- 

 lina the entire sponge consists of a single hollow cylinder, which widens 

 from the base upwards, and is most expanded near the summit. When 

 compressed, a rupture always takes place between the summit of the 

 column and the cap-formed top, which separates as a kind of lid. This 

 lid, with its central mammseform point, its radiating primary lines of 

 bundles of spicules, and its transverse secondary lines, reminds us 

 strongly of the top of a basket. In all these respects the genus ap- 

 proaches very closely to the genus Euplectella, much more so than do 

 the species of the genus Polymastia. The spicula are needle-shaped 

 (acuate), swollen in the central part, and attenuated towards the " head " 

 as well as towards the point ; but they are not " acerate " as described 

 by Dr. Bowerbank, the head end being blunt and rounded. The smaller 

 spicules sometimes assume a slightly pin-shaped (" spinulate") form. 



Pulymastia bulbosa, Bow. The type specimen. " Shetland, Mr. C. "W. Peach, 

 1864." 



spinula, Bow. In 50-110 fathoms, on stones and shells. In a speci- 

 men which has but one fistula, though its basal mass is only ^ of an 

 inch in diameter, the fistula is no less than 1| inch long, but only -$ of 

 an inch wide. Other specimens have as many as five and six fistulas. 



- radiosa, Bow. The type-specimen. " Shetland, Mr. C. W. Peach " 

 (Bowerbank). 



- mammillaris (Miiller). A single specimen in 1868, also procured by 

 Mr. Barlee. 



Tethea cranium (Miiller). Common on the Outer Haaf, sometimes attached 



* Quasillus, a little basket, 

 1868, 2 A 



