Dec. 2 (, 1871 



NATURE 



149 



same Deinosaurian class, although " its fore limbs are 

 more crocodilian," and "its pelvic girdle ni'jre lacertian." 

 And the evidence ot'fered by the articular ends of the 

 bones of the extremities being adapted for movement in 

 particular directions, the possession of large claws, and 

 the hollowness of the long bones, indicate that it was of 

 terres'rial, and not, as its name seems to imply, of marine 

 habit. It may, however, have been, as Prof. Phillips 

 suggests, "a marsh-loving or river-side animal." Its 

 gigantic size may be gathered from the fact that one of 

 the femora measures no less than 64, and a humerus 51 '5 

 inches (Fig. 4). 



Nor is there evidence wanting as to its diet. From the 

 mutilated fragment of a tooth in the O.'cford Museam, 

 Pr -f. Phillips infers that its possessor lived on vege- 

 tables, since it resembled "that of an iguanodon in gene- 

 ral shape (as far as can be known, one edije being broken), 

 with a similar Svveep of the concave surface seen in the 

 diagram, and corresponding alternation towards the edge. 

 The edge is not serrated, but the stria; of accretion are so 

 arranged as to suggest that it may have been." The 

 truth of this conclusion is proved by the subsequent dis- 

 covery of a nearly perfect crovvn by IVIr. Burrows, one 

 of my students, m the Enslow Quarry, which has very 

 much the appearance of a young tooth. It presents the 

 serrations which have been worn away in the specimen 

 above described, and bears out completely Prof. 

 Phillips's description. 



I have chosen merely these two animals as illustrating the 

 subject-matter of the book, which is in every sense worthy 

 of the high reputation of its author. W. B. D. 



PARTHENOGENESIS AMONG THE LETI- 

 DOPTERA 



'T'HE pirt of the Archives Ncerlandaises, published 

 ■'■ by the Societe HoUandaise des Sciences h. Harlem, 

 for 1870, contains the results of some very interesting ex- 

 periments undertaken by M. H. Weijenbergh, jun,, on 

 the above subject, one fraught with considerable interest 

 to others besides entomologists. By Parthenogensis is 

 meant the power that is possessed by females of pro- 

 ducing eggs endowed with vitality, and from which 

 youn;j ones are produced, without impregnation taking 

 place on each occasion. This subject has been extensively 

 treated by von Siebold in his " VVahre Parthenogenesis 

 bei der Schmetterlinge und Bienen," Leipzig, 1856, but 

 confirmatory and new investigations were much needed. 

 Those of M. Weijenbergh were conducted with every 

 possible care and precaution, so that they can be re- 

 lied upon. In the autumn of 1S66 he sav a male and 

 female of the species Liparis dispar together, and 

 some days afterwards he saw in the same place a great 

 quantity of the eggs, about 500 in number. In order to 

 leave the rearing of these to natural processes, as far as 

 possible, he left them exposed all the winter in the open 

 air, and in April 1867, he removed them into his house. 

 Before the end of the month the caterpillars had suc- 

 cessively made their appearance. These were regularly 

 fed, and by the middle of July each of the chrysalides 

 which had been formed during June gave birth to a perfect 

 butterfly. It was easy, with a little practice, to distinguish 

 the sexes whilst in the caterpillar state, and all the males 

 were removed as far as possible, and the females were 

 placed in a box closed to all access from without. So suc- 

 cessfully was this separation of the sexes effected, that 

 only one male butterfly made its appearance among the 

 females ; and, as these had been successively removed 

 to a third closed box as soon as they escaped from 

 the chrysalis state, it was only necessary to sacri- 

 fice the three or four females which were in the box 

 at the time. In all, about sixty females were obtained, 

 to which there was absolute certainty that no male 

 could by any possible chance have had access. Of 



these, two-thirds laid eggs in the autumn,— some, one, 

 two, or three eggs only ; others as many as ten or twenty, 

 but yet even at the most not one-twentieth of the eggs of 

 their mother. The other one third laid no eggs at all. In 

 all about 400 eggs were collecled, which were removed 

 and carefully packed up till April 1868, when a large 

 number of little caterpillars were seen. These were im- 

 mediately placed on leaves in a large glass vase and 

 watched carefully. It was easily to be seen that this 

 batch of caterpillars possessed far less vitality than those 

 of the previous year. A large number of the eggs dried 

 up and were worthless, some fifty caterpillars alone appear- 

 ing, and of these only about forty survived to become 

 chrysalides. From thi'se, by the end of July, twenty- 

 seven butterflies made their appearance. The same pre- 

 cautions having been taken as before, the number of 

 females was found to be fourteen. Of these, when again 

 there had been no possibility of male access, one half laid 

 no eggs, the remaining half, however, laying in all 

 a fair number. As in previous years, these were re- 

 moved and left all the winter carefully picked up, till, in 

 April 1869, three years after the commencement of the 

 experiments, young caterpillars again made their ap- 

 pearance. From these, strange to say, the number of 

 butterflies obtained vvas in excess of those oljtained in 

 the previous year. The number of females as compared 

 with males, was almost the same, in contradiction to 

 the results of other investigators, which had indicated the 

 probability of the ratio of the males to the females 

 greatly increasing with each additional year. The eggs 

 laid by the females of this year, carefully isolated as 

 before, were Dacked up during the winter, but when 

 examined in the spring of last year, 1870, no caterpillars 

 made their appearance, the eggs became shrivelled up, 

 and the experiment was at an end. There is every 

 reason to believe that it was most carefully conducted, and 

 that every regard was paid to strict accuracy during the 

 whole three years or more that the experiment vvas being 

 carried on. The results amount to these ; — 



(l.) Aug. 1866, eggs laid by impregnated female ; April 

 1867, caterpillars appear ; and, in July, perfect butterflies. 



(2.) Aug. 1S67, eggs laid by females of this year without 

 impregnation; April 1868, caterpillars appear, and, in 

 July, perfect butterflies. 



(3.) Aug. iS5S, eggs laid by females of this year without 

 impregnation; April 1869, caterpillars appear, and, in 

 July, perfect butterflies. 



(4.) Aug. 1869, eggs laid by females of this year without 

 impregnation; April 1870, no results — the eggs all dried 

 up. 



Thus, after the first impregnation of the female m the 

 autumn of 1866, three successive broods of caterpillars 

 and, ultimately, of butterflies made their appearance ; and 

 four successive times were eggs laid without further impreg- 

 nation, in three of which they proved endowed with vitality. 

 It would take a long series of experiments, each conducted 

 with the same care as this, before an average could be 

 drawn to determine the limit of this strange reproductive 

 power. These experiments are so easily performed, and 

 yet so valuable when accurately made, that a wide 

 field is opened to those who do not care to undertake 

 long and elaborate scientific investigations, and to such we 

 most cordially commend them. Their value, as bearing 

 on the theories of spontaneous generation, is very great, 

 as there is much apparent probability that this power 

 of Parthenogenesis will increase as we descend in the 

 scale of life just as it decreases as we ascend. By its 

 aid many phenomena, now apparently very strange and 

 perplexing, will be found to be but obeying one great and 

 universal l\w of nature, which becomes less visible the 

 higher we ascend in the scale of life, but yet never ceases. 



In conclusion, it may be stated that this power of Pa:- 

 thenogenesis has been found in many species of butter- 

 flies, and also among bees ; and M. Weijenbergh, at the 



