Recent Proceedings of Societies. 



Academy of natural sciences, Philadelphia. 



March 3. — Prof W. K. Brooks communicated the 

 results of observations made during the last six or 

 seven years on the development and alternation of 

 generations in the hydro-medusae organisms, which, 

 in the last term of their life-history, become a form 

 of jelly-fish after ceasing to be polyps. It is de- 

 sirable that such phenomena be traced from the 

 simple beginning to the more complex conditions. 

 The speaker gave an illustrated description of the 

 development of podocoryne, a form found on our 

 coast. When hatched from the egg, it appears in 

 the planula stage, or that of a little infusorial form 

 covered with cilia, and pushing through the water 

 by means of them, like ordinary infusoria. It soon 

 loses its cilia, and settles on the shell of a hermit- 

 crab, where, assuming the form of a root, it branches 

 freely, and soon covers the surface on which it is 

 placed. The first hydras formed from this root have 

 the appearance of ordinary fresh- water hydras. They 

 are produced to the number of two hundred or three 

 hundred, and have a mouth and a digestive tract 

 continuous with that of the root. Their function is 

 to nourish the colony. Another form of hydra is 

 soon developed. They are many times longer than 

 the first, have short tentacles greatly developed at 

 their tips, which are packed with the poisonous 

 lasso-cells by means of which prey is paralyzed and 

 captured. The latter hydras have no mouth, and 

 take no food. They depend for their sustenance on 

 the feeding-hydras which are first developed, al- 

 though they are efficient in supplying nutritive ma- 

 terial to be operated on by the latter. The so-called 

 blastostyles are now developed. These also take no 

 food themselves, nor are they defensive, but around 

 them grow the medusa buds, which increase rapidly 

 in size, and soon become larger than the whole 

 hydroid community to which they belong. They are 

 ultimately set free, and swim about like independ- 

 ent jelly-fish. Each blastostyle produces many of 

 these independent organisms. In most hydroids 

 these become the sexual form, but in the species 

 of podocoryne found on our coast there is still 

 another step before the ultimate development is 

 reached. Little buds are formed by the independent 

 jelly-fishes, wh ; ch are set free, develop reproductive 

 elements, and bear eggs, which complete the cycle 

 by again producing the planula stage. The sex in 

 these organisms is definitely determined in the 

 planula, although not fully developed until the 

 second generation of buds, each crop being all 

 male or all female, according to the kind of planula 

 producing it. In the Geryonidae a single egg be- 

 comes a single sexual individual. It passes, how- 

 ever, contrary to the general belief, through the 

 planula and hydroid stages, which are true em- 

 bryonic states, the development being a direct meta- 

 morphosis. The planula and hydroid stages of this 

 form have not been before defined. In Aegina each 

 egg hatches into a ciliated, two-layered planula, 

 which lengthens, and develops tentacles. A mouth 

 breaks through, and the planula becomes a little 

 hydra. This grows, a flange connects the tentacles, 

 and the epithelium is pushed in to form a cavity. 

 Turritopsis, a jelly-fish of an entirely different group, 

 is infested by the parasitic larva of a medusa which 



fastens itself in the angle of the pendant stomach. 

 Each parasite is provided with a long proboscis, by 

 means of which it reaches into the digestive cavity 

 of its host, and thus obtains nourishment. Little 

 colonies of these parasites, the Cuninae, ultimately 

 develop into medusae. Here there is an asexual 

 multiplication, but no true alternation of generation. 

 Another species of Cuninae is found as a parasite 

 upon geryonids. This has not been found on our 

 coast, but its history has been traced by a Russian 

 embryologist. The planula which hatches from the 

 eggs becomes parasitic in the geryonid, but it never 

 completes its development, or becomes a medusa. It 

 remains a budding-stolon, from which other hydra 

 are produced. These facts indicate, in the opinion 

 of the speaker, that alternation of generations does 

 not arise in the first place from polymorphism, or 

 from the separate existence of varied forms, but by 

 the power of the hydra larva to develop asexually. 

 Although the parasitism of Cuninae has long en- 

 gaged the attention of embryologists, many of whom 

 have gone hopelessly astray in their interpretation, 

 it is interesting to note that an American naturalist, 

 McCrady, nearly forty years ago, wrote an account 

 of the phenomena which is essentially correct. 



Microscopical society, West Chester, Penn. 

 March 9. — The committee appointed to take into 

 consideration the act of assembly passed the 23d day 

 of June, A.D. 1885, entitled " An act for the de- 

 struction of wolves, wild-cats, foxes, minks, hawks, 

 weasels, and owls, in this commonwealth," and 

 which reads as follows, — "That for the benefit of 

 agriculture and for the protection of game within 

 this commonwealth there is hereby established the 

 following premiums for the destruction of certain 

 noxious animals and birds, to be paid by the re- 

 spective counties in which the same are slain ; 

 namely, for every wild-cat two dollars, for every 

 red or gray fox one dollar, for every mink fifty 

 cents, for every weasel fifty cents, for every hawk 

 fifty cents, and for every owl (except the Acadian 

 barn or screech owl, which is hereby exempted from 

 the provisions 'of this act) fifty cents," — report that 

 all of the birds denounced in the law above quoted, 

 with rare exceptions, have been found to be the best 

 friends of the farmer. Dr. H. H. Warren, the orni- 

 thologist of the Pennsylvania state board of agricul- 

 ture, and chairman of the committee, had corre- 

 sponded with the best ornithologists in the country, 

 asking their opinion as to the benefits or injury likely 

 to arise from the execution of the law against the birds 

 therein named. Answers were received from Dr. C. 

 Hart Merriam, Robert Ridgway, Dr. Leonard Stej- 

 neger, H. W. Henshaw, and Lucien M. Turner, all 

 bearing testimony that the hawks and owls are of 

 great benefit to the farmer, and render him far 

 greater service than injury, and that it is unwise to 

 select any of them for destruction. The committee 

 stated that there have been ninety odd hawks and a 

 dozen or more owls killed since the law was passed, 

 June 23, 1885, at a cost to this county of about 

 seventy-five dollars, and that the slaughter is still 

 going on, and further urged that the members of the 

 state legislature be requested to aid in the repeal of 

 the act so far as it relates to these birds. 



Science club, Richmond, Ind. 



March 5. — Dr. Bond cited a case of cerebral local- 

 ization in his practice, where euphasia had been pro- 



