246 PROCEEDINGS OF THE ACADEMY OF [1887. 



pennsylvanica they are entirely spinecl. The spicules of Spongilla 

 igloviformis are marked with large, prickle-like spines ; and amongst 

 material collected at Deep Creek, A-'irginia, and also from 

 sedimentary deposits in Nova Scotia, still another and more coarsely 

 spined spicule has been collected, whose affiliations have not, 

 as yet, been ascertained. H. v. pictovensis differs from all these 

 in its de7ise spination and in the relatively great thickness and the 

 rounded ends of its spicules. 



Attention is asked for a moment to one fact stated by Mr. 

 MacKay in his letter transmitting the last above specimens. They 

 were gathered in midwinter from under the ice and were as I 

 can testify, of a vivid green color and from his description were evi- 

 dently still growing. The scarcity of gemmules may remind us of a 

 similar condition in the case of Spongilla aspinosa, which has also been 

 seen to be evergreen ; and of the inference then suggested that they 

 may not exist because they are not needed. 



The form alluded to as having been found at White Haven has 

 never been named, and does not need varietal designation. Its 

 general spiculation is merely more robust than that of H. rt/deri 

 in a smaller degree than that in which the spicules of v. haleni seem 

 less so. Intermediately must be placed, 



Heteromeyenia ryderi, v. walshii, n. v. 



Sponge light green; primarily sessile but soon sending out slen- 

 der, subdividing branches, palmate, with rounded terminations- 

 giving them a stag-horn-like appearance. Fronds made up of many 

 slender, nearly parallel lines of slightly fasciculated spicules, the 

 net work being completed by crossing lines of single or nearly 

 solitary spicules. 



Gemmules infrequent, spherical; crust rather slight. 



Skeleton spicules slender, cylindrical, somewdiat curved, gradually 

 or more abruptly pointed, sparsely microspined. 



Long birotulates with typical rotules of hooked rays; shafts inflated 

 at the middle, with one to five long spines. 



Rotules of short birotulates relatively large, flat ; margins lacin- 

 ulate; shafts smooth, thickening under the rotules. 



Log. Gilder Pond, Massachusetts. 



During that solitary but most enjoyable morning spent upon 

 Gilder Pond, as already described in my sketch of M. everetti, 

 I discovered, early in my explorations, that there were beneath my 

 boat two forms of branching sponges. They were not very dissimilar 



