140 PROCEEDINGS OP THE ACADEMY OP [1884. 



Note on the Amphibious Habit of Lycosa. — Dr. McCooK 

 alluded to another interesting fact in the life-history of Lycosa, 

 brought to his attention by Mr. Alan Gentry, This gentle- 

 man, during the winter, visited a pond in the vicinity of Phila- 

 delphia (Germantown) which was frozen over. He cut a slab 

 from the ice about eight to ten feet from the bank, and was sur- 

 prised to see several spiders running about in the water. They 

 were passing from point to point by silken lines stretched under- 

 neath the surface between certain water-plants. Several were 

 captured, but unfortunatelj'^the specimens were not preserved. Mr. 

 Thomas G. Gentr}'^, who saw them, says that they were Lycosids, 

 and from his description of the eyes he is evidently correct. It 

 is a remarkable and novel fact to find these creatures thus living 

 in full health and activity in mid-winter within the waters of a 

 frozen pond, and so far from the bank in which the burrows of 

 their congeners are so common]}^ found. It has been believed, 

 heretofore, and doubtless it is generally true, that the Lycosids 

 winter in deep burrows in the ground, sealed up tightly to main- 

 tain a higher temperature. But the above observation opens up 

 a new and very strange chapter in the winter behavior of these 

 spiders, as well as in the amphibious nature of their habits. 



Pentastomum proboscideum. — Prof. Leidy exhibited specimens 

 of this parasite, presented to him by Mr. Norman Spang, of Etna, 

 Pa., who recently obtained them in Florida, from the lung of a 

 large rattlesnake, Crotalus adamanteus.. They are cylindrical 

 incurved, annulated, largest and rovmded at the head, tapering 

 behind, and becoming again larger and rounded at the end ; 

 and terminating ventrally in a short conical point. There are 

 six of them, with the following measurements : — 9 lines long by 

 1^ lines at the head; 13 lines by 1^ lines; 24 by 2h', 28 by 2i; 

 30 by 3, and 31 by 3. The species was first found by Humboldt 

 in Crotalus horridus. It is common in the Boa constrictor, in 

 which Professor Leidy had also observed it several times. It has 

 likewise been found in a number of other serpents. Other species 

 occur in diflferent mammals, including man, reptiles and fishes. 

 These singular parasites are regarded as the most degraded form 

 of arachnida, in the mature stage being reduced to a worm-like, 

 limbless body. 



May 20. 

 Mr. Thomas Meehan, Vice-President, in the chair. 

 Eighteen persons present. 



The Nature of a Fasciated Branch. — At the meeting of the 

 Botanical Section on the 12th, Mr. Thomas Meehan called atten- 

 tion to a paper contributed by him to the Proceedings of the 



