NATURAL SCIENCES OF PHILADELPHIA. 125 



The largest specimen, consisting of a net emanating from three 

 divisions, occupied a semicircular space of of a mm. by 2 mm. 

 Another specimen with a central disk \ mm. by mm. with 

 its net, occupied a circular space mm. in diameter. A small 

 cord-like specimen was \ mm. long with an expanded end ^V mm. 

 wide ; and another irregular cord-like specimen was of a mm. 

 long with the widest portion ^ mm. 



Amoeba porrecta, of Schultze, from the Adriatic Sea, most re- 

 sembles the creature described. While it is nearty related with 

 Gromia, Lieberkuehnia, Vampyrella, Nuclearia, etc., it appears 

 sufficiently distinct in its characters to represent another genus, 

 and with the species may be appropriately named Biomyxa va- 

 gans. 



On Psorospei'ins in a Mallard Duck. Prof. Leidy remarked 

 that Dr. Elliott Coues had recently submitted to his examination 

 some portions of the flesh of a mallard duck preserved in glycerine. 

 The interstices of the muscles of the duck were stated, in the letter 

 which accompanied the specimens, to be everywhere occupied by 

 abundance of parasites. Specimens of these, in the portions of 

 flesh examined, proved to be oval white bodies from one to two 

 lines long, and about one-third of a line thick. Beneath the micro- 

 scope they were found to contain myriads of fusiform corpuscles, 

 resembling minute navicular, and measuring about the -^'^th of 

 an inch in length. Similar bodies were first discovered in many 

 fishes by the late Prof. J. Midler, and described by him as para- 

 sites under the name of Psorosperms. They have been repeatedly 

 observed since by Retzius, Robin, and others, in the muscles and 

 other parts of fishes, and they are usually regarded as vegetable 

 parasites. I have not previously heard of similar organisms hav- 

 ing been detected in birds. Though the mallard is not a fish eater, 

 the bird may have become infected by having swallowed an in- 

 fected fish. 



On a Uouthless Fish. Dr. George W. Lawrence, of Hot 

 Springs, Arkansas, in the course of correspondence, had mentioned 

 to Prof. Leidy the occurrence of a mouthless fish in the Ouachita 

 River. At his request Dr. Lawrence had sent him a specimen, 

 which he now exhibited to the members. The fish is the Buffalo 

 sucker, Catastomus bubalus, Kirtland, living in the Mississippi 

 and its tributaries. The specimen is fifteen inches long, and ap- 

 pears to be in good condition. The maxillaries, premaxillaries, 

 and the mandible are absent, and the integument is tightly ex- 

 tended between the end of the snout, the suborbitals, and the 

 articular ends of the quadrates. In the centre of this expansion 

 of the skin there is a small oval aperture one-fourth of an inch 

 fore and aft, and one-eighth of an inch in transverse diameter. 

 The hole is sufficient to admit a current of water for the purposes 



