94 DR.J.S. BOWERBANK ON SILICEO-FIBROUS SPONGES. [Jan. 28, 
the idea that it occurs in but very small quantities in the siliceo- 
fibrous sponges. In truth, if we compare the abundance of its pre- 
sence in this species, as well as in D. M*Andrewii and other such 
sponges which have been preserved in their natural condition, we 
cannot come to any other conclusion than that this vital substance 
is as abundant in the siliceo-fibrous sponges as it is in the Hali- 
chondroid species, and even in the true Spongie. 
DacryLocaLtyx BowERBANKII, Johnson. 
Sponge sinuously and expansively cup-shaped, sessile. Surface 
even; margin flat and angulated. Oscula simple, dispersed, nu- 
merous. Pores inconspicuous, dispersed. Expansile dermal system 
—dermal membrane abundantly spiculous ; connecting spicula fur- 
cated patento-ternate, and rarely dichotomo-patento-ternate, large 
and long; tension-spicula fusiformi-acerate, small and short, few in 
number ; retentive spicula elongo-cylindro-stellate, with very short 
radii, minute, exceedingly numerous; and elongo-attenuato stellate 
few in number. Skeleton—areas round or oval, irregular; fibre 
cylindrical, smooth, but irregularly nodulous at intervals ; nodules 
cylindrical, short, terminating hemispherically. Interstitial mem- 
brane—interstitial spicula fusiformi-acerate, long, slender, and flexu- 
ous, and same form rather short and stout; retentive spicula 
elongo-cylindro-stellate, and elongo-attenuato-stellate, the same as 
those of the dermal membrane, few in number. 
Colour, alive, white (J. Y. Johnson, Esq.), in the dried state light 
brown. 
Hab. Deep water off Madeira (J. Y. Johnson, Esq.). 
Examined in the dried state. 
The only specimen of this species known was obtained from “ deep 
water off the coast of Madeira,” by James Yate Johnson, Esq., and 
was described and named by him in P. Z. 8. 1863, p. 259. The 
general description he has there given is very correct as far as it 
goes; but he has not given a definite specific description of its cha- 
racters. The specimen is now in the British Museum. 
Dr. Gray, in his “Notes on the Arrangement of Sponges” 
(P. Z. S. 1867, p. 507), notices the specimen as a synonym of his 
genus and species MacAndrewia azorica, in the following terms :— 
«The specimen which Mr. J. Yate Johnson has described under 
the name of D. Bowerbankii is larger, more orbicular and expanded 
than I described years before as Macdndrewia azorica; but I cannot 
see any other difference.” But as the learned author has nowhere, that 
I can find, given any particulars of the structural peculiarities of the 
specimen as compared with those of his species Mac Andrewia azorica, 
his hasty assignment of it to that species is in reality devoid of any 
authority. Half an hour’s microscopical investigation of the two 
specimens which are in his possession would have completely satisfied 
him that they were very distinct species of animals, as the reader 
may readily satisfy himself by comparing the figures illustrating the 
species under consideration in Plate V. figs. 2, 3, 4, & 5, from D. 
