224 Proceedings of tlie Boyal Phjjsiccd Society. 



broad, deeper at the sides. The head and neck are very 

 narrow, relatively to the trunk, and when partially drawn 

 in look disproportionately small. 



In comparing this bdelloid with the earlier descriptions of 

 allied species, our greatest difficulty arises from the in- 

 sufficiency of these descriptions. 



From all species having less than six teeth, it is sufficiently 

 separated by that character alone. Most of those having six 

 or more teeth {e.g., C. russeola, C. magna, C. scarlatina, C. 

 anmdata, G. crenata) possess other good distinctive char- 

 acters. There are only three species known to me which 

 the new form resembles closely enough to call for detailed 

 comparison. Those are C. elegans, Ehr, C. constricta, Duj., 

 and C. leitgebii. C. elegans, which has usually more numer- 

 ous teeth, has also a much larger corona, and larger, longer- 

 pointed spurs. G. leitgebii, according to Janson, may have 

 as many as seven teeth. I identify as this species an animal 

 common among mosses from trees, which has a longer and 

 narrower neck, a very small narrow rostrum, and softer, 

 less distinctly plicate trunk. There remains only G. cojistricta. 

 The most important characters given by Janson (6, p. 56), 

 the very small corona, the number of teeth, and the small 

 spurs, fit our animal very well. Not having seen G. constricta, 

 a carefully measured drawing from the living animal was 

 sent to Mr Bryce, who knows that species. He was good 

 enough to send me examples of C. constricta, and to point out 

 an important difference. In G. constricta the corona is as 

 broad as the collar, or very nearly so, in G. microcephala it 

 is very decidedly less. The discs of G. constricta have not 

 the angled appearance of those of G. microcephala. 



Among moss from the foot of a wall at Polton, near Eoslin, 

 2nd March 1905 (Evans). It has since been seen among 

 ground moss from Fort Augustus. 



G. constricta, Duj. 



Since writing the above, G. constricta has been found in 

 moss from Hopetoun Woods, December. 



C. crenata, Murray (12). 



In moss from wall at Dalkeith, April. 



