122 SIPHOPHYCE.E. 



This is the I'aucheria polysperma of Hassall, who says of it : " It is by 

 no means uncommon, and may be distinguished from all others known 

 to me by the fineness of its filaments, which are not half so large as those 

 of our other British species, no less than by the form and arrangement of 

 the sporangia. These are slightly pedunculate, varying in number from 

 3 to 5, but usually there are but three, the apices or beaks of which are 

 neither turned towards or averted from each other, but are all directed 

 one way. The resemblance which the capsules bear to a bird's head 

 when viewed sideways is very remarkable, and this resemblance is 

 rendered still more striking by the fact that the circular sporangium 

 occupying only the central portion of each, and which therefore repre- 

 sents the eye of the bird. ' 



Plate XLVI1., Jig. 4. Oogouia and antheridia of V. sericea X 

 200. Fig. 5. Oogonia containing oospores x 200. Fig. 6. Mature 

 oospore enclosed in an oogonium X 200, after De Bary. Fig. 7. Zoospore 

 X 200, after Walz. Fig. 8. Spermatozoids. 



b. CoRNicULATxE. Antheridia bent in the form of a horn or a 

 hook, seated on short lateral branches. 



4. VauchexiaDillwyni. Ay. 



Terrestrial, broadly expanded, forming a rather thin stratum, 

 of bright or dark green colour. Oogonia globose, or ellipsoid, 

 rostrate, sessile, usually single, sometimes in twins, enclosed in 

 delicately punctate membrane. Mature oospores spotted with 

 brown, sporoderm very thick, composed of several strata. 

 Antheridia bag-shaped, formed from the apices of short lateral 

 curved branches, either approximate to the oogonia or seated 

 between a pair of them. 



Kabh. Alg. Eur. iii., 269. Grev. Alg. Britt. t. xix. Hass. 

 Alg. t. 4, f. 3. Eng. Fl. v., p. 320. Jenner Tunb. Wells 176. 

 Eng. Bot. ii., p. 124. Harv. Man. 147. Johnst. Fl. Berw. ii., 

 251. Grev. Fl. Edin. 305. Mack. Hib. 234. Fl. Devon ii., 

 56. Hook. Fl. Scot, ii., 93. Gray AIT. i., 290. 



Vaucheria Ungen, Thnr. Ann. Sci. Nat. xix. (1843), t. 13, f. 

 43? 



Vaucheria pachy derma, Walz Jahrb. p. 146, t. 12, f. 1-6. 



Conferva frig ida, Dillw. Conf. t. 10. Harv. Man. p. 147. 



Conferva amphibia fibriUosa et spongiosa, Ray. Syn. p. 59. 



On the ground in damp shady places. 



It is presumed that this is the same species as has been described by 

 Walz under the name of raucheria pachyderma, but the synonyms of some 

 of these species are a little mixed. Dillwyn says : " It is not unfrequently 

 found in turnip fields during the winter and early months of the spring, 

 particularly in a northern exposure, and on a cold soil. The patches 

 vary in size, but are usually two or three inches in extent, adhering but 

 slightly to the soil, and consisting of loose unconnected filaments." 

 " The form of the capsules, which are rarely pedunculated, will at once 

 distinguish this from all other species," says Hassall, " which have 

 hitherto been described." 



