1887.] NATURAL SCIENCES OF PHILADELPHIA. 27 



as showing that even the lower animals were not exempt from 

 morbid growths and lesions of the most serious character. 

 Tumors of the kind described in the oyster are probably very- 

 rare, however, and the speaker considered that it was very fortu- 

 nate that the sj)ecimen had fallen into the hands of a naturalist, 

 such as Professor Leidy, who could so well appreciate its import- 

 ance and value. The tumor seems to have been benign in character, 

 as the oyster in other respects appears to have been healthy. It 

 was also localized, and did not appear in other parts of the animal, 

 so that it was^ probably in no way infectious. 



Modification of Habit in Ants through fear of Enemies. Dr. 

 Henry C. McCook described a raid of the Sanguine ants, Formica 

 sanguinea, which occurred in a vacant lot at Asbury Park, N. J. 

 The co-operative nest of the two species was established quite 

 near the sidewalk, and the raid was directed thence into the 

 open lot. The marching column of Sanguines was accompanied 

 by a few individuals of the black slaves. What special purpose 

 the latter had he was not able to determine. The eagerness 

 exhibited by the Sanguines upon the march was very noticeable, 

 although these creatures are always active in the nest and at any 

 domestic labor as well as war, in which respect they differ largely 

 from the shining slave makers, Polyergus lucidus. 



On the occasion of which he spoke, the nest of Fuscous ants, 

 Formica fusca, against which the exjDedition * was directed, was 

 concealed among a large amount of forest rubbish, such as bits 

 of broken chips, twigs, dried leaves, etc., that were scattered 

 over the barren space, interspersed here and there with tufts of 

 grass and low huckleberry bushes. The invaders had evidently 

 located the nest, but not Avith absolute accuracy; at least they 

 were not able to determine the point at which it might success- 

 fully be assaulted. A most animated scene was presented over 

 the entire surface, some three feet in diameter, upon which was 

 concentrated the united energies of the warriors. Over and 

 around this space in various lines the ants wandered, crossing 

 and criss-crossing each other's pathways, sometimes singly, 

 sometimes in couples or triplets, or in larger crowds, but always 

 exhibiting an attitude of fevered eagerness, applying their mandi- 

 bles and mouth-parts continually to the ground in search of the 

 point of vantage which would give them ingress to the coveted 

 treasures of the Fuscous ants. 



A space about ten inches in diameter, strewn with dry chippage 

 seemed to represent the locality beneath which the blacks had 

 established their formicary. The Sanguines energetically pulled 

 away the chips, scattered them here and there, burrowed lightly 

 in the earth hoping to obtain an opening. About two feet 

 distant from this point the speaker discovered a small round 

 entrance or gate which was soon identified as one of the outer 

 approaches to the Fuscous nest, for several of these ants were 



