CORTTHION DUBIUM. 97 



Feic & Vavee in Arch. Landesf. Bohmen, X (1897), iii. pp. 46, 60, 60. 

 AvBBmTZEFF in Tmdui S.-Peterb. Obshch. XXX, I (1900), p. 240 ; 



op. eit XXXVI, II (1906), pp. 314^315. 

 MUEEAT in Pvoc. R. Phys. Soc. Edinb. XXV (1905), p. 615 ; in 



Batbym. Suvt. Scott. Lochs, I (1913), p. 326. 

 ScHOTJTBDEN in Ann. Biol, lacastre, I (1906), p. 372, f. 51. 

 Evans in Proc. R. Phys. Soc. Edinb. XVII (1907), table 1. 

 Hkinis in Zool. Anzeig. XXXIII (1907), p. 714; in Arch. Hydro- 



biol. V (1910), p. 110 ; in Rev. Suisse Zool. XIX (1911), p. 256. 

 Beown in Naturalist, 1910, p. 93; in Jrn. Linn. Soc, Zool. XXX, 



1910, pp. 362, 367, pi. 1, i. 13 ; in Brit. Assoc. Handb. Sheffield 



(1911), pp. 500, 501 ; in Ann. Scott. Nat. Hist. 1911, pp. 229, 230 ; 



in Naturalist, 1912, p. 181 ; in Scott. Natui-. 1912, p. 112 ; 1918, 



pp. 208, 210. 

 HoPKiNSON in Irish Natur. 1910, p. 3. 

 Wailbs & Pbnaed in Proc. B. Irish Acad. XXXI, lxv (1911), pp. 



15, 60, 61, 62. 

 Wailes in Scott. Natur. 1912, p. 60 ; in Jrn. Linn. Soc, Zool. XXXII 



(1912), pp. 126, 152; in Naturalist, 1913, p. 147 ; iu Murray's Nat. 



Hist. Bolivia and Peru (1913), p. 35. 

 Trinem.a constricta 



BETES in Mission scient. Cap Horn, VI, Prot. (1889), p. 18, f. 2. 



Test sub-circular or oviform, unsymmetrically com- 

 pressed ; transverse section elliptical ; aperture cir- 

 cular or oval, ventral, sub-terminal, oblique ; plasma 

 colourless, granular, partly filling the test ; nucleus 

 containing one or more nucleoles, placed posteriorly ; 

 one or two contractile vesicles usually present ; pseudo- 

 podia attenuatie, straight, radiating, simple or sparsely 

 branched, several usually present. 



Length 23-65 /a ; breadth 16-40 /a ; aperture 5-16 /a; 

 thickness 12-20 /a ; nucleus 6-12 /a in diameter. 



Habitat. — Mosses and sphagnum. 



G-enerally distributed. 



Although not so numerously represented, this 

 species is as widely distributed as Trinema lineare; 

 it may always be expected in any gathering of moss 

 or sphagnum. The length usually varies between 

 30 and 45 /a ; above 50 /a individuals are rare. From 

 Inishbofin, (ialway, one was obtained 87 /a in length 

 and 40 /a in breadth (similar in shape to fig. 6) . 



From Trinema enchelys it is distinguished by the 

 character of the plates forming the test. 



A spined form, var. spicata Penard,. occurs in 

 Australasia but has not been recorded from elsewhere. 



VOL. in. 7 



