196 ROYAL SOCIETY OF CANADA 



length of lit mm. No openings are visible at the distal ends of the- 

 fistula'. The pores are beautifully shown over the entire surface, both of 

 the body of the sponge and of the fistuhe. By slitting one of the latter, 

 the pores were seen leading into the interior canal as well as the opening 

 b}^ which the canal communicates with the main portion of the sponge. 

 When dry the fistuhe collapse and become strap-shaped. 



Mr. Whiteaves informs me that when fi-cshly dredged, the sponge is 

 orange-red ap|)roaching to scarlet in colour and that it is found growing 

 on rocks in patches sometimes several inches across. 



The size of the spicules in difterent specimens varies considerably. 

 The lai'ge tylostyli of the body of the sponge are from 0*479 to 1-0 mm. 

 long and from 0-006 to 0-02 mm. thick (Plate II.. fig. Gk). The cortical 

 tylostyli are from 0-260 to 00^5 mm. long with an average thickness of 

 006 mm. (Plate II., fig. 6/>). Spicules similar in size and form to those 

 of the main fibres of the body of the sponge occur in some numbers, 

 beneath the cortex, parallel to the surface. 



Localities. — South of Cow Head, Prince Edward Island, in 12 

 fathoms, seven specimens, preserved in alcohol, J. F. Whiteaves, 1873. 

 One specimen, dry, Portland, Maine, Sir William Dawson. The latter 

 specimen has fistuhe reaching a length of 35 mm. with a maximum basal 

 diameter of 4-5 mm. 



Distribution. — (rulf of St. Lawrence (J. F. Whiteaves) ; Portland, 

 Maine (Sir William Dawson) ; south of Nova Scotia (Challenger) ; north- 

 east coast of United States (Verrill). 



Foreign dis,tribnti<)n. — Coast of Northumberland (Bowerbank). 



Polymastia .mammillarfs (Miill.) Bowerbank. 



(Plate III., figs. 1, hi-d.) 



HalkJtondi la viatinii i//(i ris. .]ohnstou. ISl'J. IJritish Sponges, p. 142, pi. xvi., tig. 2, 

 Euplectella ninnniiilldi-is, Bowerbank. iWiO. List of British Marine Invertebrate 



Fauna, Rep. of Brit. Ass., p. 23(î. 

 Polijmu.stki mo iiimiilaris, Bowerliank. lWi(5. Moii. Brit. Spong., vol. ii., p. 71, vol. 



iii., pi. :'.: figs. 1 11 and vol. iv., p. 32. 

 Poll/mast if t maiuinillftri.s ^ Whiteaves. 1874. Report on deep-sea dredging oper- 



ati'>.is in the Gulf of St. L<awrence, p. 9. 

 " " Vosmaer. 18H5. The sponges of the " Willem Bar- 



ents" Expedition, ISSOand 1881, p. 14, pi. i., figs. 5, 

 Band pi. iii., figs. 10 12, 21. 

 " " Ridley and Dendy. 1887. Rep. Monaxonida Zool. ClialL 



Exp. vol. XX., p. 211. 



Represented in the collection by three specimens from the (lulf of 

 St. Lawrence. They have the usual strap-shaped fistula', as described by 

 Bowerbank, with their distal ends frequently much broader than the 

 breadth at mid -height, as well as a smaller form circular in section 

 throughout its length and with truncated, often slightly inflated ends. 



