58 SUMMARY OF CURKENT RESEARCHES RELATING TO 



an alphabetical index of species and synonyms, a bibliographical list, 

 and an index of authors. 



Metamorphoses of Cassiopeia borbonica.*— Professor G.Du Plessis 



has observed ova of what he believes to be this species, develope into 

 a fixed Scyphistoma, after passing throi;gh a free Planula-stage. 

 Other larvje of similar appearance, which had already attained the 

 Scyphistoma-stage, were studied by him at the Naples Aquarium, and 

 were seen in the middle of October to divide metamerically into 

 segments, forming the well-known Strobila-stage. The segments 

 soon became detached, constituting free Ephyrse of a similar, but 

 paler, yellow tint to that of the adult of the above species, but differ- 

 ing from it in having four simple and suckerless, instead of eight 

 ramified arms, and in having the margin of the umbrella much more 

 deeply notched. In this instance also, the attempt to rear the adult 

 failed, but as the only other species whose stages resemble these, has 

 quite a diflerent Ephyra, there seems good ground for believing that 

 we have here the full metamorphosis of a Medusa, supposed hitherto 

 to develope ametabolically. In the agreement of its physiological 

 arrangements with those groups with which it has hitherto been 

 classed, it afibrds an argument in favour of the morphological correct- 

 ness of the present classification. 



Development of Geryonopsida andEucopida.f — Professor C. Glaus 

 states that in an aquarium containing sexually mature specimens of 

 Odorchis gegenhauri, Irene pellucida, and ^quorea forshalea, he saw 

 small polyp-stocks which presented great resemblance to Campa- 

 nulina ; the elongated hydranths were placed on branched stolons, 

 the periphery of which was invested by a more or less distinct 

 periderm. There was a conical retractile proboscis, and the base of 

 the contractile tentacles was surrounded by a delicate ectodermal 

 fringe. Hydrathecfe were, however, altogether wanting ; this and 

 other differences induce the author to call this form Campanopsis. 

 The medusa-buds arise on the middle of the body of the polyp, where 

 they form one, two, or, rarely, three transverse rows ; they appear as 

 bilaminate rounded projections, the base of which soon grows into a 

 long cylindrical stalk, with a vesicular endoderm. Before the forma- 

 tion of the subumbrellar cavity, the ectoderm gives rise to a layer of 

 flat cells, which form the theca, and give rise to a closed mantle- 

 covering. The manubrium is formed from a central elevation ; the 

 radial vessels give rise to outgrowths, which are the rudiments of 

 the primary marginal tentacles. In alternate rays, as well as between 

 these and the primary tentacles, marginal vesicles become developed 

 with small intermediate thickenings — the rudiments of fresh marginal 

 filaments. When, therefore, the medusa is set free, it has two long 

 tentacles and eight adradial marginal auditory vesicles. These last, 

 which are relatively large, contain each a single otolith. At this 

 point, unfortunately, the author's direct observations cease, but he 

 adduces reasons for believing that this Campanopsis is an Odorchis. 



* Bull. Soc. Vaucloise Sci. Nat., xvil. (1881) pp. 633-8 (1 pi.). 

 t Albeit. Zool. Inst. Wien, iv. (1881) pp. 89-120 (4 pis.). 



