272 DR. J. S. BOWERBANK ON [Apr. 6, 
is known of the birds of Narborough Island, though little can be ex- 
pected here from the extreme barrenness of this island. Hood Island 
offers a better prospect; and Tower Island ought certainly to be visited. 
Nor ought the smaller islets, such as Barrington Island and Duncan 
Island, to be omitted when the collector is in search.of new ground. 
The islands already explored are well worthy of further investigation. 
Of the whole archipelago, Indefatigable Island is the only one where 
a really extensive series of birds has been obtained, though Dr. 
Habel’s collections from Bindloe and Abingdon islands are by no 
means small. 
‘In conclusion, I would recommend any one visiting the Galapagos 
to call at Cocos Island, in N. lat. 5° 33’, long. 86° 58’ W. At present 
we only know of one land bird from this well-wooded and well-watered 
island ; and that is a peculiar Cuckoo of an American genus, Coceyzus 
Jerrugineus. A collection made here cannot fail to be of high 
interest. 
Mr. Salvin’s Memoir will be printed entire in the Society’s ‘Trans- 
actions.’ 
The following papers were read :-— 
1. A Monograph of the Siliceo-fibrous Sponges. 
By J. S. Bowersank, LL.D., F.R.S., F.Z.S., &e.—Part I1.* 
[Received March 12, 1875.] 
(Plates XXXIX. & XL.) 
Farrea Gassioti1, Bowerbank. 
Sponge cup-shaped, expansive, parietes very thin; pedicel short. 
Oscula, pores, and dermal membrane unknown. Skeleton siliceo- 
fibrous ; fibres cylindrical, furnished more or less with short acutely 
conical spines; rete rectangulated ; areas mostly square; central 
canals large and very distinct, not always confluent, frequently two 
in each fibre. Interstitial spicula rectangulated sexradiate ; radii 
cylindrical, smooth, few in number. Sarcode, dried, dark amber- 
brown. 
Colour, in the dried state, brown? 
Hab. West Indies (Capt. Hunter, R.N.). 
Examined in the skeleton state. 
The type specimen is 9 lines in height. The pedicel does not 
exceed 2 lines. The cup is partially compressed ; it is 1 inch in its 
greatest marginal diameter, and 8 lines in its smallest breadth. 
I could not detect the slightest indication of either dermis or oscula. 
The primary series of skeleton-fibres radiate from the basal portion 
of the cup, the secondary ones having a circumferential direction at 
about right angles to the primary ones; they each appear to be as 
nearly as possible of the same diameter, and to have the central 
canals and the spination of the fibres equally apportioned. There 
* For Part II. see Proc. Zool. Soc. 1869, p. 323. 
