310 SUMMARY OF CURRENT RESEARCHES RELATING TO 



specific pigment-cells — as a by-product of metabolism, possibly of 

 some respiratory significance. The paper abounds in interesting histo- 

 logical details. 



f Genera of Enteropneusta.* — Prof. J. W. Spengel discusses tbe 

 terminology of tbe genera, and gives a useful systematic list of tbe 

 known forms. 



1. Harrimaniidse n.f., including Harrimania 



Dolichoglossus 

 Stereobalanus 



2. Glandicipitidte 1 . , ,. ,-,, ■>• 



o l t-, > including Glandiceps 

 syn. fepengelid*/ Spengelia _ 



Schizoeardium 



3. Pcychoderida?, including Glossobalanus 



Balanoglossus 

 Ptychodera 



Plumatella and Vivipara.f — W. Zykoff refers to Kraepelin's de- 

 scription of a " symbiosis " between Plumatella princeps Kraep. var. 

 S. spongiosa and Vivipara fasciata Mull. Zykoff found the same in 

 the Volga ; in tbe majority of cases tbe mollusc was covered all over 

 witb a thick colony of Plumatella, and the mass was sometimes as large 

 as a fist. Tbe fishermen regard them as fresh-water sponges. 



Ccelentera. 



Post-Embryonic Development of Aurelia aurita.lj:— 0. Friedemann 

 sums up bis results in the following terms : — The stages in the develop- 

 ment of the tentacles are expressed by the numbers — 4, 8, 16, 24 ; the 

 12- and 20-stages are intermediate. At the foot of the larva there are 

 glandular cells with pseudopodia. In tho stinging-knobs of the tentacles 

 the ectoderm appears at places two-layered ; the cnidoblasts send pro- 

 cesses into tbe supporting lamella and there enter into connection witb 

 ganglion-cells ; the fully formed nematocysts occur in two sizes. 



There is no " septal funnel " in Goette's sense, but in the older 

 Scyphistomas an inter-radial " peristom-funnel " arises as a new invagi- 

 nation — a transitory ectodermal proliferation into the tamiola. Nor is 

 there an ectodermic gullet. 



The endoderm cells of the gastral cavity show both extra- and intra- 

 cellular digestion. In young Scyphistomas the tajnioke do not extend 

 down more than a third of the central stomach, — in older forms not more 

 than a half. The cell-multiplication on the outermost margin of the 

 tamiolse is altogether a local differentiation of the endoderm ; a growing 

 down of the ectoderm from the mouth does not occur. 



In quite early stages there are no stomach-pouches in Goette's sense, 

 but simply grooves due to the tamiola?. In the eight-armed scypbistoma, 

 four distinct stomach-pouches make their first appearance, clothed inter- 



* Zool. Jahrb., xv. (1901) pp. 209-18. 



t Zool. Anzeig., xxv. (1902) p. 181. 



It Zeitschr. f. wiss. Zool., lxxi. (1902) pp. 227-G7 (2 pis. and 3 figs.). 



