1884.] NATURAL SCIENCES OF PHILADELPHIA. 193 



ON A SUPPOSED NEW SP CIES OF CRISTATELLA. 

 BY EDW. POTTS. 



I wish to announce the discovery in October last, within the 

 waters of Harvey's Lake, Luzerne Co., Pa., of vast colonies, or, 

 technically speaking, of aggregations of colonies of a species of 

 Gristatella, exhibiting some peculiarities that seem to distinguish 

 it from C. mucedo of Europe and from both the known American 

 forms. 



Harvey's Lake is a beautiful sheet of water, Ijang at an altitude 

 of about 1200 feet above sea-level, amongst partially wooded hills 

 of no great height, and taking rudely the shape of the capital 

 letter T. Its greatest length is about two miles. The depth 

 throughout the larger part of this extent is said to be very great, 

 increasing rapidly a few feet from the shore. The first groups of 

 this beautiful polyp were found upon a large inclined log or stump 

 in deep water, within one or two feet of the surface. Here the 

 colonies appeared as scattered vermiform masses much longer 

 than those of C. Idse of Leidy, and nearly rivaling in length 

 those of G. ophidioidia of Hyatt. The longest were estimated 

 at about six inches. Instead, however of following the sinuous 

 lines, described by the latter author as characteristic of his 

 species, these assumed, generally, single or continuous curves, 

 like a parted letter O or rude C. Afterwards, in three or four 

 instances, we found them occupying entirely novel situations. 



The tops of fallen trees or large branches lying 20 or 30 feet 

 from the shore, and spreading to a diameter of 10 or 12 feet, were 

 covered by hundreds or thousands of these colonies, clinging to 

 or twining around every branch and twig, yet with so slight an 

 attachment that the motion of raising a twig above water caused 

 them to drop ofi" by dozens. While hanging temporarily by one 

 end they assumed a spiral form, closely twisting upon themselves. 

 Their gelatinous common ectocyst, nearly a line in thickness, 

 lined the branches as far as we could reach or see. Its persist- 

 ence upon those twigs brought away with us is rather remarkable, 

 as after remaining seven months in water it is still easily recog- 

 nizable. It exhibits under the microscope a plexus of fine lines 

 like a very delicate mycelium, which indeed may now have 

 replaced the normal structure. 



