124 RESHARCHHS IX HELMINTHOLOGY AND PARASITOLOGY. 



produced as occasion may require, just as a Mytilus or a Pinna 

 renews and attaches its threads of byssus to secure its position. 



The siliceous spicules of PJuroncnia are composed, as in sponges 

 generally, of concentric layers, and exhibit a delicate tubular axis. 

 A spicula from one of the tufts measured as follows : 



Spread of the anchor i-ioth of a line ; shank of the anchor i-3oth 

 of a line; prickled portion of shaft i-4oth of a line; shaft where 

 thickest and without prickles i-i8th of a line, thinning out to the 

 inserted end where it was not more than i -300th of a line. 



The species I propose to dedicate to my wife under the name of 

 Phcroncma anncc. 



[September, 1870. Nos. 317 and 335. See Bibliography.] 



Prof. Leidy stated that during the last summer he had made some 

 further observations on Urnatella, a genus of ciliated polyps of the 

 family Pedicellinidse, discovered by him some j^ears ago (Pr. Ac. 

 Nat. Sc, 1851, 321 ; 1854, iqO i^ the Schuylkill river. It is found 

 abundantly below the dam at Fairmount, adhering to stones and 

 rocks, on the sides and under part, not in contact with the ground. 

 Occasionally it is observed attached to the shell of the living Unio 

 complanatus and Melania virginica and less frequently to the stem of 

 Schollera graminea and the leaves of l'allis7ieria spiralis. In the 

 locality named, on the rocks, there may be observ^ed, in association 

 with Umatclla, the following animals : Spongilla fragilis : Livi7iias 

 ce7^atophylli, usually abundant and in compound bunches : Cotlnirnia 

 pusilla, parasitic on Umatclla and Lininias ; Hydra car?iea, Ag., 

 Pahidicella elongata , Plnmatella vcsicularis, and the worm Manayimkia 

 speciosa, etc. 



[June, 1870. No. 326. See Bibliography.] 



Prof. Leidy next made some remarks on the family of the Vin- 

 egar-eels, the substance of which was as follows : The number of 

 .species and genera of nematoid worms represented by the Mnegar- 

 eels and constituting the family Anguillulidae is astonishingly great. 

 They are found in multitudes frequently in and about moist deca}'- 

 ing and fermenting organic substances. Mr. Ba.stian, of London, a 

 few years since contributed to the 25th volume of the Transactions 

 of the Linnean Society a paper, in which he has given descriptions, 

 with characteri.stic figures, of most of the known species, including 

 about one hundred new ones, which he observes he discovered from 

 a few limited regions in England in the course of fifteen months. 



