1887.] 



NATURAL SCIENCES OF PHILADELPHIA. 



207 



VV\J|//^ 



surface of rotules dome-shaped ; rays prolonged, terminations acute ; 

 malformations frequent. These are mixed with occasional linear 

 spined spicules. 



Gemmule spicules abundant, 

 crossing each other upon the 

 crustless, chitinous body. 

 Their .shape when smooth is 

 robust-fusiform, with pointed 

 terminations : the great ma- 

 jority, however, have from 

 one to six or more long spines, 

 non-symmetrically placed, but 

 with an evident tendency 

 to group themselves at points 

 about one-fourth the length of 

 the spicule from one or both of its extremities. 



Meas. Diameter of gemmules 0.036 inches ; skeleton spicules 

 0.0068 by 0.0002 inches ; length of average dermal birotulate, 

 0.00066 inches; and of those of the gemmulse 0.00145 inches. 

 Hab. Encrusting stones in shallow water. 



Loc. Lakes or j)onds in the vicinity of Heart's Content, New- 

 foundland ; collected by Mr. A. H. MacKay. 



As the unusual features of this sponge give it a peculiar import- 

 ance, I am tempted to co2:)y the results of an entirely independent 

 study of it bv my friend Mr. Carter, taken from a letter written to 

 the discoverer, Mr. MacKay. The comparison of it with that above 

 given may be both interesting and instructive, as showing how the 

 same peculiarities, ecjually new to both, may impress different ob- 

 servers. 



"Specimen sessile, spreading over two sides of a cubic stone about 

 two inches in diameter; about one sixth inch high in the center, 

 thinning off towards the circumference. Color of the surface 

 greenish ; of the interior greyish brown. Surface smooth, shining, 

 (in the dried state), covering a parenchymatous structure beneath, 

 traversed by thread-like bundles of the skeletal spicules of the 

 s})ecies, charged Avith statoblasts. 



Statoblasts globular, of different sizes, but comparatively large 

 generally ; being often ^VcVths of an inch in diameter ; covered in a 

 tessellated manner, by a single layer of short fusiform spicules 

 in juxtaposition and all on the same level. 



