34 REPORT ON THE PENNATULIDA. 



attached to them by one eud, but with the greater part of their 

 length lying freely in the body-cavity, and capable of being shot out 

 through special apertures {cinclides) in the body-wall. From the 

 description given above, it is evident that Finiicitlina, to use Gosse's 

 nomenclature, has craspeda, but no acontia. Heider* and others have 

 indeed doubted whether Gosse's acontia really exist in the Sea- 

 anemones. 



Concerning the function of these mesenterial filaments there has 

 been so much dispute that a few words may not be out of place here, 

 although the subject is one which we have had no opportunity of inves- 

 tigating physiologically in FunicuUna, and which, therefore, does not. 

 strictly speaking, fall within the limits of the present report. 



By different writers all possible functions appear to have been 

 assigned to these organs. Contarini, Delle Chiaje, Spix, Johnston. 

 Wagner, and Owen, describe them as the male reproductive organs, 

 either essential or accessory ; by Eapp, Cuvier, R. Jones, and Quatre- 

 faga, they were regarded either as ovaries or oviducts ; others have 

 considered them to be bile vessels ; while Frey, Leuckart, Schmarda, 

 and more recently Heider and the Hertwigs, are of opinion that as 

 they contain both gland-cells and thread-cells their main function is 

 probably that of digestive organs, the thread-cells serving to paralyse 

 or kill the prey after being swallowed alive, and the gland-cells to 

 digest it when dead. 



By far the most important evidence on the subject, however, is 

 that submitted by Dr. Krukenberg t as the result of a direct physio- 

 logical investigation of the action of the mesenterial filaments of 

 Sea-anemones. He finds that the mesenterial filaments have a very 

 considerable power of digesting albuminous substances, such as raw 

 fibrin or raw pieces of flesh : and by mixing portions of the filaments 

 with small pieces of raw meat in a very finely-divided state, he was 

 able to watch the process of solution, i.e., digestion of the meat under 

 the microscope. Furthermore, by experimenting in a similar manner 

 with portions of the stomach, tentacles, body-wall, etc., of the 

 Anemone, he was led to the important conclusion — that not only have 

 the mesenterial filaments the power of digesting albuminous bodies, 

 but that they are the only portions of the body which possess this 

 power: that they are not only digestive organs, but the digestive 

 organs of the Anemone so far as proteid matters are concerned. 



For digestion to take place it is necessary for there to be absolute 

 contact between the gland-cells of the filaments and the food ; from 

 which Dr. Krukenberg concludes that digestion is not effected by 

 means of a fluid secretion poured out over the food, but by the direct 

 those in the endoderm of the stomach. This outer capsule has its 



* Heider, loc. cit. 



+ Krukenberg Vergleichend phvsiologische Studien an deu K Listen der 

 Adria Erste Abtheilung, 1880, pp. 38-5G. Ueber den Verdauuugsmodus der 

 Actinien. For a knowledge of this interesting and important ])aper we are 

 indebted to Professor Kay Lankester, 



