EUPODISCUS. 



[ 307 ] 



EURYCERCUS. 



ing a curvilinear series j freshwater ; lengtl 

 l-i>88 to 1-216". 



E. cimex, E. (Coccudina cimex, D.). 



E. charon, E. (Plcesconia charon, I).). 



E. vannus, E. (PL vannus, D.) (PL 31 

 fig. 6). 



E. monostylus, E. (Ermha legumen, D. 

 (PI. 30. fig. 52). 



BIBL. Ehrenb. In/us. 377 ; Duj. 7w/ws 

 435 ; Stein, Infus. 158. 



EUPODIS'CUS, Ehr. A genus of Dia- 

 tomaceee. 



Char. Frustules single, disk-shaped, cir- 

 cular, without internal septa; valves fur- 

 nished with tubular or spiniform processes. 

 Marine and fossil. 



The processes are so easily broken off, 

 that the apertures corresponding to the 

 points of attachment are generally alone 

 seen. The valves appear either distinctly 

 areolar, the depressions being large ; granu- 

 lar, from their being minute ; or striated. 



Two groups are recognizable : 



a. Eupodiscus proper. Valves areolar or 

 striated. 



E. argus (PI. 16. fig. 30 : a, side view ; b, 

 front view). Valves slightly convex ; pro- 

 cesses three ; diameter 1-156". 



E. sculpttis, Sm. (PI. 16. fig. 31). Valves 

 striated, central striae forming a quatrefoil ; 

 processes two ; diameter 1-770 to 1-400". 



b. Aulacodiscus,~E,. Valves granular; pro- 

 cesses very short, their bases connected with 

 the centre" of the valve by a furrow. 



E. crux (PI. 50. fig. 43). Diameter 1-380". 



E. Petersii. Processes four, with larger 

 granules at their bases. Diameter 1-380". 



BIBL. Ehrenb. Abh. Berl 1839 ; id. Ber. 

 1844, 73, 1845, 361 ; Smith, Brit. Diat. i. 

 24 ; Kiitzing, Sp. Alg. 134 j Shadbolt, Qu. 

 Mic. Jn. ii. ; Roper, 1858, ibid. vi. ; Gre- 

 ville, Mic. Trans. 1863, 73, (Aulacodiscus) 

 1864, pp. 9, 82, 87, 1865, p. 26, 1866, pp. 5, 80. 



EUPO'DIUM. A genus of Marattia- 

 ceous Ferns. Exotic. 



EURO'TIUM, Lk. A genus of Pyreno- 

 mycetes (Ascomycetous Fungi), on the dis- 

 tinct nature of which great doubt is thrown 

 by the recent observations of De Bary. E. 

 herbariorum of authors is a mildew, common 

 upon decaying or preserved fruits, plants 

 imperfectly dried for herbaria, &c., forming 

 a whitish or yell ow crust, composed of inter- 

 woven mycelium filaments, which are deli- 

 cate when young, but become thickened and 

 often coloured with age. Upon these are 

 produced globular conceptacles or peridia, 

 from 1-15 to 1-20'" in diameter, composed 



of a distinctly cellular membrane, enclosing 

 little sacs or asci containing several minute 

 sporidia. According to De Bary, these con- 

 ceptacles are produced upon the mycelium 

 of Aspergillus, under certain unknown con- 

 ditions ; and the ordinary fructification of 

 Aspergillus is only a basidiosporous form of 

 the same plant which produces an asco- 

 phorous form in the Eurotium fruit. He 

 states that he not only found them grow- 

 ing upon the continuations of the same 

 branched mycelium filament, but that he 

 has raised Aspergillus, which fruited, from 

 the spores both of Aspergillus fruits and the 

 sporidia of Eurotium -, Eurotium could not 

 be obtained from Aspergillus spores. The 

 connexion between these forms is regarded 

 as analogous to that between Oidium and 

 Erysiphe. The fruit of Eurotium is a sexual 

 product, and originates as follows. The 

 ends of certain branches of the mycelium 

 coil up like a cork-screw, becoming more 

 closelv approximated, until at length they 

 come into contact, and form a cylindrical or 

 conical mass, marked externally by the 

 spiral lines of conjunction of the turns of 

 the filament. From the base of this mass 

 thin branches sprout, running up over it, one 

 of them fusing with its apex, forming an 

 antheridium or pollinodium, and producing 

 fertilization. After fertilization, the young 

 perithecia become segmented, the segments 

 forming shoots, which branch, the termina- 

 tions forming the asci or parent cells of the 

 sporidia. The ripe sporidia often exhibit a 

 curious form, like little cylinders with a con- 

 cavo-convex cap applied over each : these 

 appear to be the two halves of the dehiscent 

 outer membrane (exospore) ; for in the ger- 

 mination of perfectly globular forms the 

 mycelium filaments break through the outer 

 tough coat, like a pollen-tube from the inner 

 coat of a pollen-grain. The sporidia are 

 about 1-350'" in diameter, and of a light 

 yellow colour in mass. The dimensions &c. 

 of Eurotium, like those of Aspergittus, seem 

 to vary with the external conditions. 



Eurotium Rosarium, Greville (Sc. Crypt. 

 Fl.) = Sphceroiheca pannosa. 



BIBL. Berk, in Hook. Brit. Fl. ii. pt. 2. 

 333 ; Greville, Scot. Crypt. Fl pi. 164. fig. 

 L ; Sowerby (Farinaria), pi. 379. fiX 3 

 De Bary, Bot. Zeit. xii. 425 (1854) ; Riess, 

 'lid. xi. p. 134, and Fresenius, p. 474 

 1853). 



' EUR YCEROUS, Baird (Lynceus, in part, 

 Vfiill.). A genus of Entomostraca, of the 

 rder Cladocera, and family Lynceidse* 



