INVERTKBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 99 



6. Genital Bands. — The chief result of the author's investiga- 

 tions on these structures is that the sexual products are derivatives of 

 the endoderm, arising as ingrowths of endoderm cells, tubular at 

 first, but soon becoming solid. 



New Siphonophore.* — Under the name of Agalmopsis utricularia 

 Professor Claus describes a new Mediterranean form ; it is remark- 

 able for the possession of large vesicles at the end of the nemato- 

 phores, which are comparable to the vesicular appendages of Utricu- 

 laria. They are apparently hydrostatic organs, for they are directed 

 upwards in such a way as to keep the " grappling-lines " in a hori- 

 zontal position. At the base of each there is set a crown of eight 

 long stinging threads, so that the creature is provided with a veritable 

 network of prehensile organs. The author points out that these 

 parts are only modifications of what has been already observed in 

 A. Sarsii ; and while this leads us to associate the new form with 

 other species of the same genus, the structural arrangements of the 

 common stem support the view. It is to be distinguished from 

 A. Sarsii by the long stalk for the nutrient polyps, and by the rela- 

 tively broad hydrophyllia ; between every two of these latter there 

 are set six to nine tentacles with generative buds, and of these latter 

 the male forms are covered by a distinct investment. 



Histology of Hydra, f — Mr. T. J. Parker comes to the following 

 conclusions on some disputed points of structure in the common 

 Hydra. 



1. JEdoderm and Muscular Layer. — Sections of ammonic bichromate 

 specimens show the correctness of Kleinenberg's and the incor- 

 rectness of Korotneff's views as to the true connections of the fibrils 

 of the muscular layer. The large ectoderm cells taper at tlicir inner 

 ends, and each is continued into one of the muscular fibres. The 

 author considers that these are undoubtedly contractile, not, as has 

 been suggested, nervous. He also objects to the term ncuro-muscular 

 as applied by Kleinenberg to the ectoderm cell and its contractile 

 process, and to the term epithclio-muscle cell used by Korotncif, sinco 

 the two answer to what, in the higher animals, is differentiated into 

 sensory cell, sensory nerve, ncrvc-cell, motor nerve, and musclc-coll. 



Kleinenberg's discovery of interstitial tissue in tlio distal or gastric 

 region is confirmed, but no interstitial cells could bo made out in the 

 tentacles. This tells against tho view that the nematocysts are 

 formed entirely in these cells. 



2. Supporting Lamella. — This was clearly made out as a distinct, 

 though delicate, structureless membrane between tho muscular layer 

 and the endoderm. 



3. Endoderm. — Sections of osmic acid preparations show that tho 

 endoderm is, in all probability, ciliated througliout, eacli cell bearing 

 one, two, or three flagclliform cilia, nearly or quite as long as itself. 



The active amoeboid movement of tho endoderm cells during life 

 is strongly insisted on : tho psoudopodia sent out by tlicm, during 



* ' Arlxiit. Zool. lust. Wuizbtng,' ii. p. lOf). 



t Troc. Ivuy. Soc.,' xxx. (1880) not yet imbliblicd. 



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