Notices of Irish Entozoa. 517 



the appearance is widely altered, and instead of an apparently 

 inanimate mass of sordid matter, we find also a number of 

 white, rigid, elastic, straight worms, from one to two inches, 

 or more, in length, and above half a line in diameter at their 

 broadest part. 



While, then, the worm in its natural state, is soft, yielding, 

 rugose, and without any strongly marked outline, it becomes 

 when immersed for some time in fresh water the very reverse; 

 its form is then very distinct, its magnitude greatly increased, 

 its substance dense and elastic, and its whole appearance such 

 as to strike at once the most undiscerning eye. 



This property belonging to the Ecliinorynchus of expand- 

 ing and becoming rigid in water has been long remarked. 

 Thus Muller in the first volume of the ' Zoologia Danica,' p. 

 47, says of his Ecliinorynchus candidus, which is the present 

 species, "Corpus teres fere aequale, in vivis subrugosum, in 

 spiras contortum, album, subgriseum, morte vero instante, et 

 post mortem, vel aquae fluviali immissum rigescit, rectaque 

 extenditur; coloremque candidum assumit." There is a mis- 

 take here respecting the animal becoming rigid during or af- 

 ter death, for it is only when immersed in fresh water that 

 the change takes place, and if the specimen die without be- 

 ing so situated, no such alteration happens. In the same 

 work Muller describes the Ecliinorynchus Acns, also, under 

 another name, viz., Ech. lineolatus, (p. 48), and as a species 

 distinct from his Ech. candidus, and says that worms of this 

 kind are rugose, "aquae vero fluviatili immissi rugositatem 

 et spiralem contorsionem amittebant, recti brevi et rigidi ex- 

 tensi, glabri facti sunt." 



Rudolphi states farther of the Echinorytichi in general, that 

 according to the experiments made by Treutler and himself, 

 a part of the worm cut off becomes equally turgid as in the 

 entire animal, and that if a part be intercepted by a ligature, 

 or the proboscis be cut off, or the neck tied, the same thing 

 occurs ; whence he infers that the pores absorb equally on all 

 parts of the body. Vide 'Entoz. Hist. Nat.' vol. 1, p. 254 * 



I find much difficulty in attempting to account for this re- 

 markable imbibiton of water. It is a process evidently diffe- 

 rent from the absorption of fluids by a vital action, as it takes 

 place as readily in the dead worm as in the living. I am 

 much inclined to attribute it to endosmosis, though I have 

 not been able to ascertain the existence of any counter cur- 

 rent of fluid from the interior. One circumstance, however, 

 which may seem favorable to this idea is, that in various fluids 



*I have repeated these experiments and obtained similar results. — J. L. D . 



3d2 



