HARDWICKE'S SCIENCE- GOSSIP. 



245 



two hairs from the interior of the calyx are shown 

 in the bottom of the field of view, for comparison. 



The calyx having been carefully removed, the 

 third growth (b, fig. 149) was found to be adherent 

 to the stamen, as shown in fig. 153 ; its shape was 

 that of a pointed reniform leaf, the petiole being 

 applied to the filament, and the line of junction 

 easily seen ; but no such line of demarcation could be 

 distinguished between the anther and the leaf, the 

 structure of the one merging insensibly into that of 

 the other. This leaf was also reflected on itself at 

 various points, and was of a much deeper colour 

 than any other part of the flower, in fact, it was of 

 quite an orange-colour. 



Fig. 153. 



It is also noticeable that while the anther bore 

 plenty of pollen, the nectary at the base of the 

 filament was totally obliterated, so that the usual 

 inducement for insects to effect fertilization was not 

 offered. There were no indications of any ab- 

 normal growths at the other two sutures of the 

 flower. Richard C. Baigent. 



SPAWN OP PROGS AND TOADS. 



YOUR correspondent G. M. Doe, in Science- 

 Gossip for September, 1S75, asks what is the 

 difference between the spawn of frogs and toads, 

 and whether eggs arranged in single strings are 

 toad's spawn ? 



Some years ago I reared both frogs and toads 

 from the egg to the perfect animal, and on referring 

 to drawings taken at the time, find that toad's 

 spawn is figured iu strings, and frog's in lumps. I 

 remember seeing large masses of the latter lying 

 in a shallow pond near Bristol on March 1st, 1862, 

 and plunging my hand into the bitter cold water, 

 found it difficult to drag out a small enough 

 quantity to put into the narrow neck of a pickle - 

 bottle provided for the purpose, because, as I 

 tried to grasp at the smooth transparent conglo- 

 meration of clear eggs, with little black spots in the 

 middle of each, like currants in jelly, the slippery 



mass quietly evaded my hold, slid heavily back 

 into the water, and stirred up the mud. So firmly 

 were these apparently impalpable clusters of spawn 

 (say from 4 to 12 inches iu diameter) glued as it 

 were to themselves and to each other by the gela- 

 tinous covering that surrounds each embryo, that 

 the lumps seem heavier to the touch than to sight. 



With toad's spawn it is different ; this has to be 

 more carefully looked for, being much smaller, and 

 very likely, as your correspondent says, " in single 

 strings." My drawing gives a string of spawn con- 

 taining a double row of eggs. It is 2 inches long, 

 lying over the stem of a piece of hornwort, and was 

 found in a deeper pond near Bridport. Each white 

 egg is only about the eighth of an inch in diameter ; 

 the black spots in the middle are smaller and darker 

 than the frog's, as also are the tadpoles. Toads' 

 eggs are sometimes half an inch in diameter. Un- 

 fortunately I have not kept dates of the different 

 stages of development (as I now should, and would 

 recommend all observers to do the same), and there- 

 fore do not know how long a time transpires, after 

 the egg is laid, until the young tadpole is hatched. 

 Probably this and all stages of development depend 

 greatly upon light and temperature. Once I kept 

 a tadpole a whole year before it turned into a frog. 

 The spawn is usually to be found in March. 



In England we have two toads and one frog, — the 

 common frog {Rana temporaria), the common toad 

 {Bufo vulgaris), and the aristocratic toad or natter- 

 jack {B. calamita). I have reared only common 

 toads and frogs. Nothing is more interesting than 

 to watch the metamorphoses during the larval 

 state. In both species the young can be watched 

 through the transparent egg, which is very small 

 when laid, but afterwards swells, and is largely 

 composed of water. The speck of a tadpole in the 

 centre gradually enlarges into a round black ball ; 

 soon the tail uncurls, the head eats its way through 

 the gelatinous covering, and the tadpole is free, 

 appearing with a fringe or tuft of external gills on 

 either side of the head, and remaining generally on 

 or near the eggs until these are eaten up. In a few 

 days they seek other food, the external gills dis- 

 appear, the animal breathes by internal gills or 

 branchia adapted for breathing air dissolved in 

 water, and swims actively through the water by 

 means of a fish-like tail : at the base of this a pair 

 of legs are eventually seen budding. When these 

 are fully developed, the front limbs spring from 

 behind the head, the tail becomes gradually ab- 

 sorbed, the animal breathes by lungs, and hops out 

 of the water a perfect frog or toad, as the .case 

 might be, breathing atmospheric air. The tails do 

 not really drop off, according to popular belief: if they 

 do, why has no man ever seen them ? It would be 

 waste of material ; in nature nothing is wasted. 

 The tadpoles' tails are absorbed, not lost. I have 

 watched them gradually growing shorter, and have 



