126 LAWEBNCE M. LAMBE ON 



Spicules. — Megasclera ; of three sizes : (1) Long, generally somewhat curved, smooth 

 styli (Plate III., fig. 5a), up to 0'530 inm. in length and with an average width of 

 0-009 mm. ; occurring in the upper portions of the sponge. (2) Stout, slightly curved, 

 gradually and sharply pointed, smooth styli (Plate III., fig. 5b), from 0-235 to 0-393 mm. 

 long, with an average thickness of 0-014 mm. ; mixed with the larger spicules of the upper 

 parts of the sponge and forming the skeleton of the stem and lower parts of the branches. 

 The smaller spicules of this size are found in the surface brushes. (3) Long, slender, irre- 

 gularly bent, smooth, sharply pointed styli (Plate III., figs. 5c, 5d) up to 0-393 by 0-0049 

 mm. in size ; occurring in all parts of the sponge ; those found in the stem are smaller than 

 those of the terminal cups. The spicules vai-y much in size and seem to grade one into the 

 other, those of the stem being shorter than those found in the upper parts of the sponge. 



The above diagnosis is based upon a single but well preserved dried specimen from 

 Chika Island, Alaska ; the description of the external form will doubtless have to be 

 enlarged when additional specimens are obtained. 



It is the author's wish to connect with this interesting species the name of Dr. W. H. 

 Dall, to whose investigations in the Alaskan Arctic Ocean, Behring Sea and the North 

 Pacific Ocean science is so much indebted. 



AxiNBLLA RUGOSA, Bowerbank. 

 (Plate IV., figs. 2, 2a, 2b.) 



Dictyocylindrua rugosw, Bowerbank. 1866. Mon. Brit Spong., vol. ii., p. 119; vol. iii., p. 51, pi. xx., fig?. 1-4. 

 Axinella rugosa, FristeJt. 1877. Sponges from the Atlantic and Arctic Oceans and Behring Sea (translation), 

 Vega-3xpeditionen8 vetenskapliga arbeten, p. 461. 



Four specimens of this sponge represent this species in the collection ; they agree 

 admirably with Bowerbank's description and figure. The largest specimen, 85 mm. in 

 height, divides close to the base into two main branches which subdivide above into lobate 

 expansions. The other specimens are smaller, but have a similar style of growth. 



The spicules of the Alaskan sponges are: megasclera, of three kinds: (1) Large, 

 smooth, sharply pointed oxea (Plate IV., fig. 2), occurring in the subsidiary fibres passing to 

 the surface ; their maximum size is about 1-57 by 0-027 mm. (2) Long, slightly curved, 

 smooth styli (Plate IV., fig. 2a), thickest at midlength, up to 1-02 by 0-027 mm. in size; 

 found in comparatively small numbers mixed with the oxea at the surface. (3) Long, irre- 

 gularly bent, smooth oxea (Plate IV., fig. 2b), up to 1-7 by 0-027 mm. in size; occurring in 

 the axial fibres. These spicules are occasionally rounded at one or both ends, becoming 

 stylote or strongylote. 



The spicules of this species attain a large size, but show a considerable variation in 

 length and thickness. The spicules of the axial fibres difter from those of the subsidiary 

 fibres principally in being twisted and generally longer. 



Localities. — Chika Island and Unalaska Island. 



SUBERITES SUBEREA, Johuston. 



(Plate IV., figs. 3, 3a— d.) 



Halichondria suherea, Johnston. 1842. British Sponges, p. 139, pi. xii., iigs. 5, 6, also p. 197. 



Halina suherea, Bowerbank. 1861. List of Brit, marine invert, fauna, Report Brit. Assoc, 1860, p. 235. 



