Miscellaneous. 263 



the meantime my only concern was to introdiTce t&is undoubtedly 

 interesting little freshwater Medusa into literature, under a desig- 

 nation and description which would enable it to be re-identified, and 

 so I must search out for it among its companions the best possible 

 position according to the knowledge of it which we at present 



LeptomedusoR. 



Thaumantida?. 



Gen. nov. Halmomhes (from o\//»;, saltwater, and 

 fjiaeiv, to hate). 

 Sp. nov. lacustris. 



"Without marginal bulbs, cirrhi, or marginal vesicles. Umbrella 

 hemispherical, 16-18 (? 24) tentacles, with gentle bulbous thickened 

 bases, on the outer side of each of which an ocellum (simple ring of 

 pigment). Velum thin, but broad ; manubrium powerful, with 

 broad base, bluntly quadrangular ; mouth without lobes, cruciform, 

 the four clefts in the direction of the angles. Atrium small, but 

 distinct. Four radial canals, greatly widened in the central three 

 fourths of their length, projecting towards the sub-umbrella ; beset 

 at this point with frill-like gonads, owing to the development of 

 which they become coiled. The last peripheral third of the radial 

 canals narrow, running straight. 



Size, 2-2| millim., diameter of the bell. Colour hyaline, faintly 

 yellowish. Gonads yellowish brown. 



Locality : freshwater lagoon on the east coast of Trinidad, south 

 of Mayaro Point, in a cocoa-nut plantation. — Sitzrmr/sherichte der 

 Naturforscher-Geselhcliaft hei der UniversitiU Dor])at, Bd. ix. Heft 2, 

 1891, pp. 282-288. 



On the Causes affecting Variations in Linaria vulgaris. 

 By Thomas Meehan. 

 Few subjects more deserve the attention of thoughtful students of 

 biology than the extent of variation aside from the conditions of 

 environment. Instructive papers bearing on evolution are continu- 

 ally appearing, the full value of which is impaired by the passing 

 suspicion that the authors have not fully perceived how great is the 

 innate power to vary, independent of any external influences. That 

 environment or surrounding circumstances have considerable in- 

 fluence on the production of new forms may surely be admitted with- 

 out detriment to a profound belief that very much more is due to a 

 tendency to change implanted in the organism, the laws governing 

 which the keenest scrutiny has hitherto been baffled in the effort to 

 detect. It is possibly from this confession of ignorance that the 

 advocates of change by environment have gained so much strength. 

 He who has something tangible to please us has more power than 

 he who has to confess that he does not know. Those of us who 

 would not have conceded as much to environment as is frequently 

 claimed for it, can only insist that change is evidently going on in 

 order, and evidently in accordance with a I'egular plan ; while if all 

 claimed for environment were conceded to be sound, it would subject 

 change to the mere chapter of accidents, and the harmony and the 

 exact dependence of one thing on another, which everywhere pre- 

 vails, could scarcely exist. 



