HARDWICKE'S SCIEN CE-G OSSIP. 



We have said this pretty creature is called the 

 "jumping" mouse, aud very correctly is he named, 

 although we have never, as stated by Godman,* 

 seen it elude our "most eager speed by clearing 

 five or six feet of ground at every spring." Our 

 efforts to measure their longest leaps were not 

 altogether satisfactory, but doubt if they ever 

 reached three feet. A half-tamed specimen, when 

 chased about a room, would usually, in leaping, 

 about clear a breadth of Brussels carpet, i. e. 

 twenty-seven inches. Doubtless, in their native 

 haunts they exceed this, but we have never seen a 

 Jersey mouse double it, on any ground, cleared, 

 grassy, or woodland. 



It must not be thought that leaping is this 

 animal's only mode of locomotion. It can as easily 

 and as rapidly run as any of the mice. Indeed, it 

 is only when frightened, whether pursued or not, 

 that it leaps rather than runs away. Why should 

 this mouse have this advantage over its cousins ? 

 It is very natural to ask this, especially when the 

 " reason why " of every fact in zoology is being so 

 carefully sought out. We have puzzled ourselves 

 with this query for a long time, and close obser- 

 vation has suggested to us this mere ghost of a 

 solution, viz., that whether in woodland or in 

 meadows, we have found these mice almost inva- 

 riably where the grass or underbrush was exceed- 

 ingly dense, and usually long also ; and where, 

 therefore, the ability to leap above rather than to 

 run through such tangled vegetation was an advan- 

 tage in eluding the pursuit of enemies, especially 

 such as could only run upon the ground ; and again, 

 it is only in escaping from danger that the ability 

 to leap, such as possessed by this animal, is advan- 

 tageous to it, so far as we can determine. Nothing 

 but escaping from a pursuing foe, in the habits of 

 the animal, suggest the desirability of great leaping 

 powers, either in its nesting, food-gathering, or 

 the character of the localities frequented by it. 



Again, it is the most timid, certainly, of all the 

 mice, and if now, or in times past, it has, or has 

 had a swift-footed enemy, then the advantage of 

 being able to elude pursuit by long leaps rather 

 than by running would be of great service, and the 

 better jumpers having thus the better chance of 

 escaping, would unquestionably leave a more nume- 

 rous progeny inheriting this advantage ; so that in 

 time natural selection would in this way gradually 

 eliminate the slower-footed and less nimble indi- 

 viduals, and secure to the descendants of the more 

 ancient form that increased length of the hinder 

 limbs which is now the one marked peculiarity of 

 the lively little Jaculus. 



A word and we have done. It has not been our 



furnish the occasion for it to go into a state of the most 

 profound lethargy." 

 * "American Natural History," vol. i. p. .321. 



experience, in studying this mouse, to find that it 

 was strictly nocturnal in its habits, as stated by 

 Audubon.* That it is more lively and active then 

 than during the day is certainly true ; but it is not 

 an unusual sight to see them in broad daylight, 

 during summer, running to and fro with their cheek- 

 pouches distended with food that they are busily 

 hoarding away in their underground nests ; and 

 sometimes the females do not leave their little ones 

 behind when sunning themselves, but move with 

 apparent ease with one or more babies hanging to 

 their teats; and it is well known that when frightened 

 they will bound away with all their little ones, and 

 give as long leaps as though not thus encumbered. 

 Charles C. Abbott, M.D. 

 Trenton, N. J., U.S.A. 



THE GLOW-WORM'S LIGHT. 



nyrOTWITHSTANDlNG its notoriety, there is 

 -'-^ still much doubt associated with the economy 

 of this insect. Possessing such a peculiar, noticeable 

 property, we are not surprised that it attracted the 

 attention both of the Greeks and Romans. Aristotle 

 (" Hist. Anim.," 1. iv. c. 1) says the glow-worm is 

 found both in a winged and apterous state. If, as 

 some believe, the glow-worm of Aristotle and that 

 of this country are identical, then he was referring 



Fig. 66. Male Glow-worm. Fig. 6/. Female ditto. 



to the sexes ; but he tells us (1. v. c. 17), the wing- 

 less kinds proceed from a small, black, hairy grub, 

 and are finally metamorphosed into winged creatures 

 termed bostrychi. There is some confusion here ; 

 the name Pygolcmpis (i. e. " sbining-tail ") evi- 

 dently points to the female, which in L. nodiluca 

 is wingless, but which in L. Italica has wings. It 

 is likely, then, that Aristotle confounded these two 

 species. 



The larva of our common glow-worm agrees with 

 the philosopher's description in changing, soon after 

 it has emerged from the Qg^, from a whitish to a 

 sable hue. 



Pliny is plainer. He dilates on the light which 

 Aristotle does not even mention. He says the 

 luminosity, or, as he terms it, the colour, emanates 

 from the sides and posterior portion of the beetle 

 (laterum et clunium colore). (" Hist. Nat.," 

 1. xi. c. 34.) 



• Audubon and Bachman, "Quad, of North America," 

 vol. ii. p. 252, 8vo. ed. 



