a new Species o/Spongilla/zwtt Nova Scotia. 19 



Spongilla lacustn's, var. lacustrioid.es, Potts (the Ameri- 

 can representative of S. lacustris, auct.), from Lakes 

 Macintosh, Forbes, Lochaber, and Black Brook, 

 East Kiver, St. Mary's, respectively. 



Meyeniafiuviatilis, auct. Garden-of-Eden Lake. 



Everefti, Mills. MacKay's Lake. 



Heteromeyenia Byderi, Potts. MacKay's Lake. 



argyrosperma, Potts. Garden-of-Eden Lake. 



Together with a specimen of another species which, until 

 just now that I have had occasion to examine it more parti- 

 cularly, I thought had been Spongilla fragilis, var. segregata. 

 However, it turns out to be very different ; and being new, I 

 herewith append its description under the name of 



Spongilla Mackayi. 



Sessile, spreading, charged with little subglobular bodies 

 like large statoblasts, about 1-1 2th inch in diameter. Skele- 

 tal spicule acerate, slightly curved, sharp-pointed, more or less 

 thickly spined, averaging 50 by 2i-6000ths inch in its greatest 

 diameters ; accompanied abundantly by a minute birotulate 

 flesh-spicule precisely like that of Meyenia Everetti, that is 

 3 to 4- 6000ths inch long, with very thin smooth shaft about 

 four times longer than the diameter of the rotule, which is 

 l-6000th inch, toothed, with the teeth recurved. Statoblast 

 globular, consisting of a thick chitinous coat filled with the 

 usual germinal matter, from which is very slightly prolonged 

 an everted trumpet-shaped aperture ; bearing slight traces 

 externally of microcell-structure and the polygonal tissue : 

 making one of twenty such which are so arranged as to form 

 a subglobular body of the size mentioned ; situated around a 

 central cavity with their apertures inwards • the whole sup- 

 ported by statoblast-spicules of various sizes, which, inter- 

 crossing each other, form a nest-like globular capsule in 

 which the outer parts of the statoblasts are fixed and covered ; 

 apparently (for the specimen is dry) deficient at one point, 

 which leads into the central cavity. Statoblast-spicules ace- 

 rate, sharp-pointed, like the skeletal spicules, but becoming 

 much shorter and more coarsely spined as they approach the 

 chitinous coats of the statoblasts, where they may be reduced 

 to at least 27-6000ths inch in length, although often increased 

 to 4-6000ths inch in thickness, and their spines, which are 

 very irregular in size and situation, often as long as the spi- 

 cule is broad. Size of specimen about l-6th inch high and 

 2 inches in horizontal diameter. 



2* 



