ENCYSTMENT OF TARDIGRADA. 851 



claws, the large size, and the habitat in water. The pharynx is figured with three 

 slender rods, of which the first is longest. 



M. dispar agrees closely with this description, except as to the pharynx, in which 

 the first two rods are joined. It has a spiny egg (Plate I. fig. 11). 



Another species, having the same type of claws, M. ambiguus, Murray (Plate I. 

 fig. 10) (26), and resembling M. dispar in all other characters, has also a spiny egg. 



M. furcatus, Ehr. (11), another large species having claws of the macronyx type, 

 likewise has a spiny egg (fig. 1 lb). 



Considering that all the species known to me having claws of this particular type 

 also had spiny eggs, and that Dujardin makes no mention of the egg of M. macronyx, 

 I would have been inclined to recognise the animal which I have called M. dispar as 

 the type of M. macronyx, and would have amplified the description by ascribing to 

 it spiny eggs. 



Various authors have, however, professed to recognise M. macronyx in an animal 

 which lays smooth eggs in the cast skin. 



Greeff, in 1866 (16), p. 120,— Plate, in 1888 (30), p. 536,— Lance, in 1896 (20), 

 p. 204, — Lauterborn (21), in 1906, — Richters, in 1904 (32), p. 63, ascribe to the 

 animal smooth eggs which are deposited in the skin at the moult. Greeff and Lance 

 figure claws which agree with Dgjardin's figures of M. macronyx. 



Richters (32), p. 63, ascribes to Doyere the assertion that the eggs are laid in the 

 cast skin ; but as Doyere's paper appeared in 1840, and M. macronyx was described in 

 1851, Doyere can only be referring to Dujardin's unnamed Tardigrade of 1838, 

 afterwards called M. lacustris. 



Greeff (16), p. 105, probably originated the belief that M. macronyx laid the eggs 

 in the skin by identifying M. lacustris as the young of M. macronyx, an absurdity on 

 the face of it, as M. lacustris was said by Dujardin to lay the eggs in the skin, and he 

 made no such assertion about M. macronyx. 



It is not clear how far these various authors had for themselves verified the fact of 

 the laying of smooth eggs in the skin, in association with claws of the macronyx type, 

 or whether they were in some cases repeating statements made by others. 



Professor Richters has sent me preparations of M. macronyx, which agreed fully 

 with M. dispar as to claws and pharnyx, but it was not demonstrated that the actual 

 individuals mounted had either come from, or had deposited, smooth eggs. 



In this unsatisfactory state of affairs, and in view of the large body of authority for 

 the belief that M. macronyx lays smooth eggs, I judge it best in the meantime to retain 

 M. dispar, though having a strong suspicion that it will prove to be Dujardin's 

 macronyx. 



The species observed by Professor Lauterborn, whether it be the true macronyx 

 of Dujardin or not, was at any rate a species which he believed to lay the eggs in the 

 skin at the moult, and therefore quite distinct from that studied by me. 



