92 A. H. MACKAY ON 



Genus II.— METENIA, Carter. 



Statoblasts generally surrounded by a minutely cellular crust charged with 

 birotulate spicules in a radial position, their axes normal to the chitinous capsule 



5. — Meyenia Everetti. 



1884. Meyenia Everetti, Mills. 



1885. " " MacKay. 



ISST " •' Potts (Proc. Acad. Nat. Soi., ISST, pp. 230-3). 



Sponge green, consisting of numerous, slender, straggling filaments, little more than 

 the one-sixteenth of an inch in diameter, made up of centre lines of closely fasciculated 

 skeleton spicules about 0.008 inch, with short, thin lines of the same, diverging at acute 

 angles. Dermal spicules, minute birotulates, about 0.0006 inch long, with slender, cylin- 

 drical shafts and cap-like rotules notched at the margins into five or six hooks. Stato- 

 blasts large, about 0.02Y inch in diameter, its birotulate spicules averaging 0.0025 inch in 

 length, shafts smooth, slender, widening towards the rotules, which are formed of five or 

 six recurved, acuminate hooks. 



Habitat — Mackay's Lake near watershed of Nova Scotia in Pictou County. A few 

 dermal birotulates (if not those of S. Terrœ-Novœ or some other species) have been found 

 in the diatomaceous deposits from Ben's Lake, Pictou County ; and also from sediment 

 from the lakes supplying the water works of Halifax, which the author received from 

 Prof. Lawson. 



[Note. — There are three interesting sponges known with minute birotulate, dermal 

 spicules nearly identical. They are /S. Terrœ-novœ, S. Bohmii, Hilgeudorf, and M. EvereUi. 

 The first has been found in Newfoundland alone by the author, if Wierzejski's Galiciau 

 sponge is not identical with it. The second has been found iu Ugalla Eiver, near Lake 

 Tanganyika, Central Africa. And the third has been fouud only in a pond on Mount 

 Everett, 1,800 feet above the sea, in the south-west corner of Massachusetts, and in the 

 localities above named in Nova Scotia.] 



6. — Meyenia fluviatilis. 



1*745. Spongia fluviatilis, Linn. 



1*788. " canaliiim, Linn. 



181G. Spongilla pulvinata, Lamarck. 



1842. . " fiiiviatilis, Johnston. 



1849. " Meyeni, Carter. 



1856. " fluviatilis, Lieberkiihn. 



1863. " " Bowerbank. 



186*7. Ephydatia fluviatilis, Gray. 



18*75. Spongilla asperrivia, G. M. Dawson 



18*75. " stagnalis, 



181*7. " " Vejdovsky. 



1880. " astrosperma, Potts. 



1880. " polymm-pha, 



