AT THE MICROSCOPE. 35 



the three dorsal portions of the thorax fused into one for support 

 of the limbs. There is no corresponding sternal plate. The 

 delicate, beautifully undulating lines are folds of the skin, whereby 

 the creature is enabled to expand from the size of a pin's head to 

 that of a Horse-bean without inconveniencing itself. Imagine this 

 nnnnrnnnni ^ section through part of the skin of the 

 fOUU UUUlJl/l/ back ; if it could be pulled out, how greatly 

 extended a surface it would cover ! or, better still, take half a sheet 

 of foolscap paper, and fold it into half-inch widths lengthwise ; 

 see into how little compass it will go, and then draw it out ; 

 does it not excite involuntary astonishment that so extended a 

 surface could be got into so small a compass ? 



Glass larva (PI. VIL, Fig. i). — A popular account of this 

 by E. Ray Lankester will be found in the Popular Scie?ice Revie^v 

 for Oct., 1865, p. 605, and Professor Rymer Jones read a paper 

 on it before the Royal Microscopical Society, on June 2nd, 1867, 

 which will be found at p. 99 of the Qiiartei'ly Journal of Microsco- 

 pical Science for October of that year (Trans.). The Professor's 

 account has his usual charm of graphic style. " There are many 

 points," he says, " of high physiological importance susceptible of 

 solution by a careful examination of this insect in its different 

 stages of growth, which in other species would seem hopelessly 

 beyond research, owing to their dark hue and the general opacity 

 of their integuments ; whereas the Glass larva, as it is not unfre- 

 quently called, seems eminently constructed for the purpose of 

 courting our observation, inasmuch as it might almost be regarded 

 as purposely intended for inspection — one of those peepJioles left by 

 Providence, through which a glimpse may be obtained of the elaborate 

 machiiiery of creationy (The italicising is my own.) The account 

 has, however, a failing common to the Professor's writings, of 

 over-highly wTOught, sensational descriptions ; as, in speaking of 

 the parts of the mouth, he must have it that there are ''''formidable 

 fangs," " ^^rt-^/y apparatus," "to pass the victim easily along the 

 deadly road," and the like. Could the poor insect see the veteran 

 Professor sitting down to demolish his chop, methinks it might 

 retort with more reason on the knife, fork, and other truly formid- 

 able weapons he used in the process. The Professor's attention 

 was specially directed to the endeavour to ascertain how the meta- 

 morphoses took place, from a creature breathing at the tail, to one 

 breathing just behind the head, with, however, but partial success. 



The flm-like hairs appended in pairs to each segment have 

 been described by Huxley (after Leydig) as "peculiar sensory 

 organs, articulated with a catcli and spring " (see the article, 

 " Te<^umentary Organs,'' in Todd's " Cyclopaedia of Anatomy and 

 Physiology "). The larva is said to feed upon the Water-flea, 



