250 PROGKESS OF MICROSCOPICAL SCIENCE. 



been tabulated and reduced to curves, aud otherwise arranged for 

 reference in considering the questions of climate on which they bear. 



" Many sj)ecimens in natural history have been stored in aboiit 

 seventy packing-cases and casks, containing, besides di-ied specimens, 

 upwards of 500 store-bottles and jars of specimens in spirit. 



" I need only further add that, so far as I am able to judge, the 

 expedition is fulfilling the object for which it was sent out. The 

 naval and the civilian staff seem actuated by one wish to do the utmost 

 in their power, and certainly a large amount of material is being 

 accumulated. 



" The experiences of the last three months have of course been 

 somewhat trying to those of us who were not accustomed to a sea-life ; 

 but the health of the whole party has been excellent. There has been 

 so much to do that there has been little time for weariness ; and the 

 arrangements continue to work in a pleasant and satisfactory way." 



The Enemies of Difflugia. — Professor Leidy remarks* that in the 

 relationship of Difflugia and Amceha we would suj^pose that the 

 former had been evolved from the latter, and that its stone house 

 would protect it from enemies to which the Amoeba would be most 

 e xi)osed. The Difflugia has many enemies. " I have repeatedly ob- 

 served an Amceha with a swallowed Arcella, but never with a Difflugia. 

 Worms destroy many of the latter, and I have frequently observed 

 them within the intestine of Nais, Prlstina, Cluetogaster, and ^solo- 

 soma. I was surprised to find that Stentor polymorjyJms was also fond 

 of Difflugia, and I have frequently observed this animalcule containing 

 them. On one occasion I accidentally fixed a Stentor by pressing 

 down the cover of an animalcule cage on a Difflugia, which it had 

 swallowed. The Stentor contracted, and suddenly elongated, and 

 repeated these movements until it had split three-foui-ths the length of 

 its body through, and had torn itself loose from the fastened Difflugia. 

 Nor did the Stentor suifer from this laceration of its body, for in the 

 course of several hours each half became separated as a distinct 

 individual." 



On the Bevivijication of Botifer vulgaris. — In a paper before the 

 Academy at Philadelphia, Professor Leidy observes that during the 

 search for Ehizopods, having noticed among the dirt adhering to 

 the mosses in the crevices of our pavements many individuals of the 

 common wheel-animalcule, Botifer vulgaris, he had made some obser- 

 vations relating to the assertion that they might be revivified on 

 moistening them after they had been dried up. Two glass slides, 

 containing beneath cover glasses some dirt, exhibited each about a 

 dozen active living Eotifers. The glass slides were placed on a 

 window ledge of my study, the thermometer standing at 80°. In the 

 coui'se of half an hour the water on the slides was dried up, and the 

 dirt collected in ridges. The next morning, about twelve hours after 

 drying the slides, they were placed beneath the microscope. Water 

 was applied and the materials on the slides closely examined. On 

 each slide a number of apparently dried Eotifers were observed. 



* 'Pioc. of Acad, of Sci., riiilaaolphia,' p. 75, 1874. 



