Wyvillethomsonia, gen. nov. 



Sponge body subsplierical, attached by a stem. In the 

 summit of the sponge, i.e. the end farthest from the stem, 

 there is one large oscuhim, which is fringed by long, delicate, 

 biacerate spicules. The interior of the sponge body consists 

 of several cavities which open into the osculum. The stem 

 is prolonged through the body as an axis, and consists of 

 numerous biacerate spicules somewhat more robust than 

 those fringing the osculum, and mixed with these are a 

 number of anchoring spicules (fusiformi-recurvo-ternate of 

 Bowerbank), the recurved end being always directed to the 

 point of attachment (which in this case is a small stone). 

 The body is composed of a large number of spicules (furcated 

 attenuato-patento-ternate of Dr. Bowerbank), the radii of the 

 ternate spicules meeting each other as they lie on the surface 

 of the sponge, form a remarkable loose network -like pattern ; 

 the long pointed process from the central boss projecting 

 inwards towards the axis of the sponge. 



The Avhole of the body of the sponge and of the stem is 

 covered by a thin sarcode layer which abounds in stellate 

 spicules varying much in size. One remarkable spicule 

 (bifurcated expando-ternate) seems to terminate the axis in 

 the centre of the large osculum. 



W. Wallichii, sp. nov. (Plate II, figs. 1 to 6.) 



Habitat. — Dredged from a depth of 1913 fathoms, October, 

 1860, in lat. 58° 23' N., long. 48° 50' W., by Dr. WaUich, 

 who was then Acting Naturalist to H.M.S. " Bulldog," Sir 

 r. L. McClintock, R.N., commander. 



I name this genus and species after my friends Professor 

 Wyville Thomson and Dr. WaUich. The name of Wallich has 

 been long since employed in botany as a generic term, other- 

 wise I should have employed it as such here. Those Avho 

 may object to the length of my generic name I may remind of 

 the precedent I have in Vaughanthomsonia. I could not com- 

 memorate two more original workers than Drs. Wallich and 

 Thomson. There can be little doubt but that the three spe- 

 cimens dredged of this species are in a very young condition, 

 but from what we know of sponges generally I think it is 

 fair to assume that a mere question of size of specimen is of 

 very little consequence in determining a species ; indeed, 

 once the sponge arrives at that stage of its existence that it 

 forms all its characteristic spicules, neither the form of 



