28 ANNUAL OP SCIENTIFIC DISCOVERY. 



as by Cliamisso and Sars, in cases where the budding individual differed 

 much in form from the egg-laying one, the subject has been systematized, 

 generalized, with an attempt to explain its principle, and greatly advanced, 

 especially, and in a highly interesting manner, in Von Siebold's late treatise, 

 entitled " Wahre Parthenogenesis bei Schmeterlingen und Bienen," in which 

 the virgin production of the male or drone-bee is demonstrated. Von Sie- 

 bold, having subjected to the closest microscopic scrutiny and experiment 

 the conclusion to which the practical Bee-master, Dzierson, had arrived, rel- 

 ative to the cause of queen-bees with crippled wings producing a swarm ex- 

 clusively of drones, has demonstrated that the male bee is produced from 

 a,n egg which has been subjected to no influence save that of the maternal 

 parent; whilst such egg, if impregnated, would have produced a female or 

 worker bee. The now well-investigated phenomena of parthenogenesis in 

 Hydrozoa, have resulted in showing, as in the analogous case of Entozoa, 

 that animals differing so much in form as to have constituted two distinct 

 orders or classes, are really but two terms of a cycle of metagenetic trans- 

 formations, the acalephan Medusa being the sexual locomotive form of 

 the agamic rooted budding polype, just as the cestoid trenia is of the cystic 

 hydatid. In Hydrozoa (hydroid polypes, or sertularians) the young are pro- 

 pagated, as in plants, by " buds," and also, as in most plants, by " germs " 

 or " seeds : " these latter are contained in " germ-sacs " projecting from the 

 outer surface, which is another analogy to the flowering parts of plants. 

 The first acquaintance with these marvels excited the hope that we were 

 about to penetrate the mystery of the origin of different species of animals; 

 but as far as observation has yet extended, the cycle of changes is definitely 

 closed. And, since one essential step in the series is the fertilized seeds or 

 egg, the Harveian axiom, " omne vivum ab ovo" if metagenetic phases be 

 ascribed to one individual, may be still predicated of all organisms which 

 bear unmistakable characters of plants or of animals. The closest obser- 

 vations of the subjects of these two kingdoms most favorable to clear in- 

 sight into the nature of their beginning, accumulate evidence in proof of 

 the essential first step being due to the protoplasmic matter of a germ-cell 

 and sperm-cell ; the former preexisting in the form of a nucleus or protoplast, 

 the latter as a granulous fluid. In flowering plants it is conveyed by the 

 pollen-tube, in animals and many flowerless plants, by locomotive spermato- 

 zoids. The changes of form which the representative of a species undergoes 

 in successive agamically propagating individuals are termed the " metagen- 

 esis " of such species. The changes of form which the representative of a 

 species undergoes in a single individual, is called the "metamorphosis." 

 But this term has practically been restricted to the instances in which the 

 individual, during certain phases of the change, is free and active, as in the 

 grub of the chaffer, or the tadpole of the frog, for example. In reference 

 to some supposed essential differences in the metamorphoses of insects, it 

 had been suggested that stages answering to those represented by the apodal 

 and acephalous maggot of the Diptera, by the hexapod larva of the Carabi, 

 and by the hexapod antennifcrous larva of the Meloe, were really passed 

 through by the orthopterous insect, before it quitted the egg. Mr. Andrew 

 Murray has recently made known some facts in confirmation of this view. 

 He had received a wooden idol from Africa, behind the ears of which a 

 Blatta had fixed its egg-cases, after which the whole figure had been rudely 

 painted by the natives, and these egg-cases were covered by the paint. Xo 

 insect could have emerged without breaking through the case and the paint; 



