252 PROCEEDINGS OF THE ACADEMY OF [1887. 



localities within eleven separate states, including the last arrival from 

 Newfoimdland. This specimen was peculiar, in so far as the larger 

 rotules deviate from the ordinary rule of entire margins and are 

 found divided into irregular rays or rounded segments. The smaller 

 rotules are clearly rayed, and very irregular in size. 



Generally speaking, the specimens gathered were filmy, indicating 

 but a single years growth. At AVhite Haven however, the frag- 

 ments brought up by my "scraper net" from piling standing in 

 deep water above the dam were, in some cases, a quarter inch or 

 more in thickness ; suggesting a serial growth somewhat like that of 

 Meyenia leidyi. 



The first records of this discovery describe the outer rotules as 

 one fifth the diameter of the inner but varying in a few instances 

 from this proportion to near equality. It required the experience 

 of several years to convince me that, a.s, in specimens from different 

 localities the prevailing proportions of the rotules differed in like man- 

 ner, their relative sizes were no guides as to species. As a result of 

 this teaching some names, given to supposed new species, must be 

 ignored ; including T. fanshcnvei, intended to honor a gentleman to 

 whose courtesy I am indebted for the opportunity of making many of 

 these explorations ; and T. intermedia, supposed at one time to be a 

 connecting link, but now known to be the species itself, in one of its 

 multiform conditions. 



Far up among the Pennsylvania mountains, fully 1800 feet above 

 the sea, is Bear Lake, one of the sources of the Lehigh River. 

 During a hurried hour or less spent upon it, one autumn day in 

 1883, we found, jas its most characteristic feature, the rocks and 

 rounded boulders in shallow water covered Avith a thin, light green 

 sponge containing some gemmules. Repeated examinations, made 

 after reaching home, showed it to be a Tuhella of very delicate and 

 fragile character as to its spicules, and exhibiting some pecul- 

 iarities that I am not as yet prepared to describe. I have marked it 



Tubella pennsylvanica, v. minima, Potts. 



Sponge light green, encrusting, thin; texture loose and incoherent, 

 sarcode having a granular appearance not fully understood. 



Gemmules few ; chitinous coat and granular crust both thin ; 

 the latter embedding a relatively very small number of insequibiro- 

 tulates. 



Skeleton spicules slender, acuminate or somewhat rounded, 

 entirely spined ; spines perpendicular, cylindrical ; terminations 

 rounded. 



