ALLOGROMIA FLUVIALTS. 141 



which shows a side or an oral view of the test, viz. 

 Leidy, PL LVII, fig. 3, a great similarity to Lieber- 

 kuehnia wageneri is evident, but neither an aperture 

 nor a peduncle is indicated, which is unfortunate, as 

 it is on the characters of these features that the 

 certain identification of the genus to which the species 

 may belong depends. 



The large single nucleus described by Leidy pre- 

 cludes us, granting the correctness of his observation, 

 from identifying this species with L. wageneri, and it 

 is differentiated from L. paludosa, which often has 

 such a nucleus, by its smaller size and thin test. 



Further examination of specimens and more definite 

 information as to the generic and specific character- 

 istics of the species are much to be desired. 



2. Allogromia stagnalis (Gr. S. West), Hopk. 

 (Plate LIV, fig. 3.) 



Ch'omia stagnalis 

 WEST in Jrn. Linn. Soc., Zool. XXVIII (1901), pp. 331-332, pi. xxix, 



f. 28. 



AVERINTZEFF in Trudui S!-Peterb. Obshch. XXXYI, n (1906), p. 270. 

 SCHOTJTEDEN in Ann. Biol. lacustre, I (1906), p. 362, f. 58. 



Test chitinoid, spherical, smooth, colourless or 

 straw-coloured, very thin and transparent ; aperture 

 small, not readily visible ; plasma usually green in 

 colour, a large amount exuding from the aperture, 

 flowing all over the exterior of the test, and giving 

 rise to numerous divergent and anastomising pseudo- 

 podia ; nucleus single, small, often not visible, situated 

 in the posterior region of the plasma. 



Diameter 28-32 /x. 



Habitat. Amongst Lemna minor in stagnant ditches. 

 ENGLAND. Near Brigg, Lincolnshire. 



As we have not seen this species, the above descrip- 

 tion is adapted from that of Prof. West (loc. cit.), who 

 says : " This beautiful Rhizopod occurred in abundance 

 in the sediment collected by washing and squeezing 

 Lemna minor and a few species of filamentous algse." 



