ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 743 



there may be one or more siphons. The palpones or tactile organs, 

 the cystones or anal bladders, the seizing organs and touch-iilaments, 

 the bracts or covering pieces, the gonostyle or generative stalk, and 

 the gonophores or generative persons are all separately dealt with. 

 The Disconaathse have one order, the Disconectae, in which tlie family 

 DiscalidfB is new. Among the Siphonanthge we have the Calyconectse 

 as the equivalent of the Calycophoridas, the Physonecta^ for the Physo- 

 phoridse, and the new order of Auronectae, and the Cystonectse, which 

 are equivalent to the Pneumatophoridse. 



Life-history of Epenthesis McCradyi, n. sp.*— Prof. W. K. Brooks 

 describes the life-history of an interesting Hydro-medusa (^Epenthesis 

 McCradyi n. sp.), remarkable and indeed unique in the possession of 

 " buds which, like egg-embryos, recapitulate, in their own ontogenetic 

 development, larval stages which their parent has already passed." 



The medusa carries on its reproductive organs campanularian 

 hydroid blastostyles, inclosed in chitiuous gonangia. These do not 

 multiply by budding or form hydroid corms, but produce medusae by 

 budding. 



The ectoderm of the blastostyle is produced by ordinary gemmation, 

 and is directly continuous with the ectoderm of the medusa. The 

 endoderm has no direct connection with that of the medusa, though the 

 germ cells from which it arose were probably in remote origin endo- 

 dermic. The germ cells form the endoderm of the blastostyle by a 

 process of specialization like that which Metschnikoff has described in 

 Cunina as sporogenesis. The blastostyles and their medusa buds have no 

 direct nutritive communication with the medusa. They are parasites 

 upon the tissue of its reproductive organ. 



The Eucopidse, to which Epenthesis belongs, is not among the 

 families in which proliferous medusae are common. Haeckel doubts the 

 occurrence of budding in the family. The new species under discussion, 

 however, certainly produces buds, and it is very probable that another 

 species, E. foUiata, multiplies asexually by fission. Brooks notes that 

 his drawings (made in 1881) of E. foUiata in all essential particulars 

 duplicate those recently published by Lang in regard to his Gastroblasta 

 raffaelii. " It is not improbable that Gastroblasta raffaelii is also an 

 Epenthesis which in addition to this power (of multiplying by fission) is 

 also able to build up, by incomplete fission, polygastric medusae of con- 

 siderable size." Just as Lang pointed out how his species illustrated 

 the way in which a form like Porpita may have been evolved from a 

 polygastric medusa, so Brooks notes that Epenthesis 3IcCrachji, with its 

 pendant blastostyles hanging from a swim-bell and carrying medusa 

 buds, stands in a somewhat similar relation to the ordinary Siphono- 

 phores. 



Arachnactis and Cerianthus.t— Prof. C. Vogt has no doubt that 

 Mr. Alexander Agassiz is wrong in thinking Arachnactis to be a larval 

 form of Edwardsia. It is an Anthozoon which swims about during the 

 whole of its life, exhibits in its organization a well-marked bilateral 

 symmetry, and is closely allied to the Cerianthidee. Cerianthus is an 

 animal which is strictly bilateral in its symmetry, for its body is divided 



* Stud. Biol. Lab. Johns Hopkins Univ., iv. (1888) pp. 147-62 (3 pis.), 

 t Arch, de BioL, viii. (1888) pp. 1-41 (3 pis.). 



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