OCTOBEK 16, 1885.] 



SCIENCE. 



339 



To further verify the fact, he frightened the chip- 

 munk, and brought home the half eaten young 

 mouse, which I examined, and found to be of the 

 species above mentioned. 



Writers on our natural history have much to con- 

 demn in the carnivorous propensities of the red 

 squirrel (Sciurus Hudsonius Pallas), of the flying 

 squirrel (Sciuropterus volucella, (Pall) Geoff), the rats 

 and shrews, but the chipmunk escapes without vitu- 

 peration. 



Speaking of the food of the striped squirrel, Audubon 

 says, in ' Quadrupeds of North A.raerica,' " it prefers 

 wheat to rye, seems fond of buckwheat, but gives 

 preference to nuts, cherry-stones, the seeds of the red 

 gum or pepperidge (ISTyssa multiflora), and those of sev- 

 eral annual plants and grasses." He mentions the 

 case, reported to him by a Boston lady, of a ground 

 squirrel which was seen taking young robins from the 

 nest. This, he thinks, was an "unnatural pro- 

 pensity in the individual," and did not indicate " the 

 genuine habit of the species." 



Dr. C. Hart Merriam, in his ' Vertebrates of the 

 Adirondack region,' says " the striped squirrel feeds 

 upon a variety of nuts and roots, and is fond of corn 

 and several kinds of grain." It is especially fond of 

 beech nuts, and stores up the seeds of various plants, 

 as of the buttercup ; eats the tubers of the ground 

 nut (Aralia trifolia), and the yellow ' kernels ' of 

 squirrel-corn (Dicentra Canadensis). He quotes from 

 a writer in the American naturalist, who saw a 

 chipmunk " busy nibbling at a snake that had been 

 recently killed. He could hardly be driven away, 

 and soon returned to his feast when his tormenters 

 had withdrawn a short distance." 



It is commonly known that the red squirrel is car- 

 nivorous to the extent of eating coccoons of insects 

 in the spring, devouring bird-eggs, and even taking 

 the young birds from the nest ; and it is quite pos- 

 sible that the chipmunk, which is rarely seen in trees, 

 may become emboldened to treat the smaller ground- 

 building birds in a similar fashion. The wholesale 

 destruction of birds, which is often rightly attributed 

 to the red squirrel, may be shared in to some extent, 

 at least, by the no less active Tamias. 



F. H. Herrick. 



Recent Proceedings of Societies. 



Academy of natural sciences, Philadelphia 

 Oct. 6. — Mr. Charles Morris made a communication 

 on the subject of attack and defence, as determining 

 agents in animal evolution. In considering the develop- 

 mentof the dermal skeleton of animals, with its vari- 

 ous modifications, we are led almost to the conception 

 that nature has been controlled at successive periods 

 by special ideas, each dominant during a long period 

 and then abandoned in favor of a new one. We 

 are quite sure that the first appearance of fossils in 

 the rocks does not indicate the first appearance of 

 life upon the earth. Early fossilization is due to the 

 preservation of the dermal skeletons of animals of 

 considerably advanced organization, and these were 

 very probably preceded, during a long era, by soft- 

 bodied forms of low organization, which could leave 

 no trace of their existence, except in the case of the 

 borrowing worms. The development of an external 

 skeleton seems to have come like a new idea to 

 nature, and was adopted simultaneously, as it seems, 

 though probably at considerable intervals by the 



various types of life. At a later era, the prevailing 

 tendency is not to assume armor but to throw it off. 

 The labyrinthodont amphibians were clothed in ar- 

 mor, their heads in particular being protected by 

 hard, bony plates. Modern amphibians are naked- 

 skinned animals. The reptiles are usually scaled, 

 but with the exception of the crocodiles and turtles 

 and some few fossil types, they do not seem to have 

 been clothed in bony armor, while in the birds and 

 mammals all defensive armor is lost. The same 

 tendency to pass from the armored to the unarmored 

 state is seen in invertebrate hfe. These changes 

 were held to have taken place in consequence of the 

 reciprocal influence of attack and defence. If a 

 food animal gained some structural feature which 

 gave it an advantage over its carnivorous foes, the 

 latter would be at a disadvantage until they had 

 gained equivalent features. So, if a carnivorous 

 animal gained some habit, motion, or weapon, which 

 gave it an advantage in destroying, this must have 

 acted as an incitement to a corresponding develop- 

 ment in food animals. Illustrative facts were freely 

 given to support the belief that four successive ideas 

 emerge into prominence in the development of the 

 animal kingdom. In the primeval epoch it is prob- 

 able that only soft-bodied animals existed, and the 

 weapons of assault were the tentacle, the thread 

 cell, the sucking disk, and the like unindurated wea- 

 pons. At a later period, armor became generally 

 adopted for defence, and the tooth became the most 

 efficient weapon of attack. Still later, armor was 

 discarded, and flight or concealment became the main 

 methods of escape, and swift pursuit the principle of 

 attack, while claws were added to teeth as assailing 

 weapons. Finally, mentality came into play, intel- 

 ligence became the most efficient agent both in at- 

 tack and defence, and a special development of the 

 mind began. As a culmination of the whole, we have 

 man, in whom mentality has replaced all other agents 

 in the strusrgle for existence. But side by side with 

 man all the other types exist, the soft-bodied, the 

 armored, the swift moving, and those in which cuq- 

 ning precedes the higher mentality. In the existing 

 conditions of life on the earth, we have an epitome 

 of the whole long course of evolution. Prof. Heilprin, 

 while agreeing in the main with Mr. Morris's argu- 

 ments and deductions, remarked the occurrence of 

 certain conditions among early organic forms, 

 which, from the position defined, would be anomal- 

 ous. The Cambrian trilobites, the largest organ- 

 isms apparently of their time, were already clad in 

 very perfect armor. Was this the result of evolution 

 without the necessity for defence ? The most highly 

 armored ganoid fishes are those of the shortest period 

 of existence. The huge carboniferous amphibians 

 are cased in armor, without the existence of con- 

 temporaries at all powerful enough to inflict damage 

 on them ; while at the present time the unprotected 

 ant eater lives side by side with such armored forms 



as the armadillo, Mr. Eedfield called attention to 



the fact that in the vicinity of Mt. Desert the traces 

 of glacial action were very obscure, and stated that 

 this had been accounted for by the theory that the 

 region had been submerged for a sufficient length of 

 time to remove the striae from the softer rock. On 

 the hard quartz veins the scoring was evident, while 

 farther inland the slates and softer deposits bore clear 

 traces of glacial scratching. The subject was further 

 considered by Mr. Aubrey H. Smith and Prof. Heil- 

 prin, the latter holding that the geologists were apt to 



