MAEINE SPONGES OF BEITISH COLUMBIA, ETC. 73 



(2) oxyasters (Plate VI, fig. li), diameter varying from O'OIS to 0003 mm. Examined 

 when dry. y^X^Aj 



Locality. — Strait of G-eorgia near Comox, Vancouver Island, in four fathoms. ' /s}^ os */ <^ 



HEXACTINELLIDA. " 



Bathydoeus Davs^soni. (Sp. nov.) ^^H/ 



(Plate IV, fig. 2 and Plate VI, fig.s. 2, 2', 2a, 2a', 2b, 2b', 2c, 2d-i, 2k.) 



Sponge (Plate IV, fig. 2) nearly or quite erect, straight or slightly curved, sub- 

 cylindrical, about 2*75 mm. in height, with a small base where it has a diameter of 20mm. 

 At midheight the maximum diameter is 50 mm. whence it gradually decreases in breadth 

 until it has a diameter of 85 mm. at its upper extremity. Tha wall has an average thick- 

 ness of *7 mm. becoming thinner near the oscular margin which is provided with a fringe 

 of long, smooth, diact marginalia with pointed ends and having an average length of 50 

 mm. The surface exhibits regularly distributed openings with an average diameter of 

 05 mm. and is rendered villose by the presence of long, sharp pointed, smooth pleuralia 

 which have a maximum length of about 60 mm. The gastral surface is smooth and has 

 openings similar to those seen in the dorsal. Texture soft. Colour in spirit light yellowish- 

 grey. 



Skeleton. — (Plate VI, fig. 2.) Composed of a loose lattice-like reticulation of long, 

 smooth diacts which lie subparallel to the surface. 



Spicules. — The pai'enchymalia consist of: (a) principalia, long, slender, smooth, sharp 

 pointed diacts (oxea) with a maximum size of 1106 mm. by O'l mm. (Plate VI, fig. 2') ; 

 (b) comitalia, long, slender, smooth diacts which have rough inflated and generally bluntly 

 pointed but sometimes round, club-shaped ends (Plate VI, figs. 2a, 2a', 2b, 2b') ; maximum 

 size 8'8 by O'Ol mm. These comitalia frequently develop two or four rounded tubercles 

 or elevations at the centre. Besides these there are the following : (c) intermedia. (1) nu- 

 merous oxyhexasters (Plate VI, fig. 2c), having an average diameter of 006 mm., with 

 long, bent, smooth terminal rays, (2) numerous oxyhexacts, with straight, smooth, 

 pointed rays (Plate VI, fig. 2d) ; average diameter 0085 mm. By the subdivision of one 

 or more rays of the oxyhexacts, forms like the oxyhexasters are evidently developed, as 

 modifications between these extreme forms are numerous. (3) Small discohexasters 

 (Plate VI, fig. 2e) with strong principal rays bearing about six short, slightly diver- 

 gent, straight terminals. Hypodermal pentacts (Plate VI, figs. 2f, 2g) with a smooth 

 proximal ray about 8 mm. in length, occur in the dermal skeleton. The four tangential 

 rays are spined, generally curved slightly inward and are about one-third the length of 

 the proximal ray. The dermal membrane includes a large number of small rough 

 pentacts and tetrads (Plate VI, figs. 2h, 2i) whose rays are about 0"06 mm. in length. 

 The gastral skeleton is devoid of hypogastralia and consists of numerous rough oxyhexacts 

 (Plate VI, fig. 2k) with rays averaging 0"06 mm. in length. 



* !> 



' A single specimen of tliis species, wliicli is in tlio Mu.seuin of tlie Geological yuivey, had j^reviously been 

 collected by Dr. G. M. Dawson, in 1S78, ofl'Cumsbewa Harbour, Qu(;en Charlotte Island, in twenty fathoms. 



Sec. IV., 1892. 10. 



