558 SUMMARY OF CURRENT RESEARCHES RELATING TO 



black or brown pigment ; males, females, and hermaphrodites (with one 

 ovary and one testis) occur mixed in the same colony, and are indis- 

 tinguishable externally ; there are twelve plumes, each with a terminal 

 bulb, in the epidermal cells of which are refractive colourless beads ; 

 free eggs, about 0*45 mm. in diameter, are found in the cavity of the 

 tubarium. 



The author compares the six known species, gives a diagnostic key, 

 and discusses the relations between Rhahdopleura and Gephalodiscus. 

 He proposes the new sub-generic title Idiothecia for those species, e.g. 

 C. nigrescens and C. levinsensi, in which the polypides reside in separate 

 tubular cavities in the tubarium, and Demiothecia for those in which 

 the polypides live together in the same cavity. The "problematical 

 body " of Harmer is shown to be formed of obliquely interlacing cross- 

 striped muscle-fibres. The clear refractive beads in the end-bulbs of 

 the plumes of G. hodgsoni are regarded, not as rhabdite cells, but as the 

 material of the tubarium in process of secretion, after the manner of the 

 globules of mucus in a goblet-cell. 



Rotatoria. 



Digestion and Excretion of Chlorophyll in Rotifers.* — P. de 

 Beauchamp has studied the digestion of chlorophyll-granules by Rotifers, 

 when fed with green flagellate organisms, such as Eaglena. The chloro- 

 phyll is at first absorbed by the cells of the stomach, then undergoes a 

 gradual change from green into brown, and forms a layer of brown 

 granules of angular shape in these cells. These granules, which resist the 

 action of acids, but swell and are slowly dissolved by strong potassium 

 hydrate, finally congregate in each cell in a mulberry-shaped mass within 

 a kind of vacuole, and are thus expelled into the stomach-cavity. The 

 chlorophyll, therefore, is not absorbed into the organism, but separated 

 and expelled by the stomach-cells, and this curious and characteristic 

 process appears to be constant in all Rotifers. The author then shows 

 that substances other than chlorophyll are also excreted in the same 

 manner by the stomach-cells. It is seen, therefore, that the stomach of 

 Rotifers, consisting of a single layer of similar cells, is able to sort out 

 the substances it absorbs, rejecting at once some in the form of granules 

 with acid reaction, and retaining others as reserve material in the form 

 of slightly alkaline proteid and fat globules. 



Notommata (Copeus) cerberus Gosse.f — P. de Beauchamp gives a 

 fuller description of this Rotifer, at the same time removing it from the 

 genus Copeus in which Gosse had placed it, for reasons fully set out. 

 The author figures the large auricles, which Gosse had not seen, and 

 describes in particular the contractile vesicle of the excretory system as 

 forming the posterior part of the intestine, separated only from the 

 latter by a constriction, and provided with vibratile cilia, which are 

 never seen in the normal contractile vesicle of other species. The 

 lateral canals issue in a single trunk from this vesicle, which is 

 really a cloaca, since the oviduct also opens into it. This arrangement 



* Comptes Rendus, cxliv. (1907) pp. 1293-5. 

 t Zool. Anzeig., xxxi. (1907) pp. 905-11 (3 figs.). 



