[lambb] sponges from THE ATLANTIC COAST OF CANADA 201 



longissimum and Lovén's Hyalonema horcdle are only varieties of the 

 same species. He accepts only one sj)ecies, and under the name of 

 Stylocordyla borealis places H. boréale. Lovén. H. longissimum. Sal's, 

 Stylocordyla borealis, Wyville Thomson, and Polymastia stipitata, 

 Carter. 



It is interesting to note that in the Canadian specimens the large 

 oxeote spicules of the stalk and of the radiating fibres of the head have 

 a decided central inflation. The largest of these specimens (Plate I., 

 fig. 11) is about 67 mm. high and has a small, narrowly rounded head 

 4 mm. high and 2 mm. broad ; its stem is comparativel}' stout, about 1*3 

 mm. thick at mid-height and 2 mm. thick just above the expanded basal 

 portion. Another and much smaller specimen is onl}' 29 mm. high and has 

 a very large head in proportion to its size and a stalk about O'T mm. thick 

 at mid-height ; its broadly ovate head is 51 mm. in length and 43 mm. 

 broad. A small, slightly raised osculum, not quite circular in outline, 

 with a maximum width of 0-5 mm., is situated a little to one side of the 

 summit of the head. In another individual the head is swollen above 

 and constricted in the lower part ; its height is 7 mm. and its maximum 

 breadth 45 mm. ; the stalk has an average thickness of 05 mm. Some 

 of the specimens have subcylindrical heads rounded slightly at the apex. 

 ]n many cases the stalk is ver}^ slender and does not exceed O'oo mm. in 

 thickness. 



The measurements of the spicules of a large specimen are as 

 follows : — 



Oxea of the stalk ; average length 1'5 mm., average thickness 0-032 

 mm. (Plate I., figs. 11a, 11^). 



Small cortical oxea of the stalk ; varying in length from 0'052 to 

 0'078 mm. and with an average thickness of 0-003 mm. (Plate I., fig. 

 Uc). 



Oxea of the radiating fibres of the head : maximum length 0*753, 

 maximum thickness 0*013 mm. (Plate I., figs, lid, lie). 



Large cortical o.x.ea of the head ; varying in length from 229 to 

 0*458 mm., with an average thickness of 0*006 mm. (Plate I., fig. 11/). 



Small cortical oxea of the head; slightly larger than those of the 

 stalk, from 0*085 to 0*104 mm. long and 0004 in average length. 



It seems likely that some specimens of this sponge may have oxeote 

 sjDicules in which a central inflation is well developed, whilst other speci- 

 mens of the same species from the same or a different localit}- may have 

 spicules in which the inflation is only slightly indicated or not developed 

 at all. 



Distribution. — Gulf of St. Lawrence (J. F. Whiteaves) ; northeast 

 coast of the United States (Yerrill) ; south of Halifax, !N"ova Scotia 

 (Challenger). 



Foreign distribution. — Iforth Sea and coast of Finmark (Loven) ; 

 off the coast of Finmark (Vosmaei*) ; Lofoten, ISTorway (Sars) ; between 



