EUASTRUM. 



[ 304 ] 



EUCHLANIS. 



genus Kiitzing refers Rivularia plicata, atra, 

 and perhaps applanata of Harvey. These 

 plants are interesting on account of the 

 fibrous decomposition of the gelatinous 

 sheaths. 



BIBL. Harvey, Brit. Mar. Alg. 222, pi. 

 26 A (Rivularw) ; Kiitzing, Sp. Alg. 339 ; 

 Tab. Phyc. cent. ii. pis. 74-82. 



EUAS'TRUM, Ehr. A genus of Des- 

 midiaceae. 



Char. Cells single, compressed, deeply 

 divided into two segments, which are gene- 

 rally pyramidal and furnished with circular 

 protuberances, lobed or sinuated at the mar- 

 gins, and emarginate at the ends. 



Ralfs describes twenty-one British spe- 

 cies, of which the following are the most 

 common. 



* Segments deeply lobed; end lobe distinct, 

 cuneate, partly included in a notch be- 

 tween the lateral lobes. 



E. vei-rucosum (PI. 14. fig. 14). Rough ; 

 segments three-lobed, lobes broadly cuneate, 

 with a shallow notch ; length 1-207". 



E. oblongum (PI. 14. fig. 15). Smooth, 

 oblong ; segments five-lobed ; lobes cuneate ; 

 emarginate; length 1-156". 



E. crassum. Smooth; segments three- 

 lobed, subquadrilateral ; end lobe cuneate ; 

 length 1-190 to 1-130". 



** Segments sinuated; end lobe exserted and 

 united with the basal portion by a distinct 

 neck. 



E. didelta (PI. 14. fig. 16; 17, empty 

 cell). Segments with inflated base, inter- 

 mediate tubercles, and notched and scarcely 

 dilated ends; side view, four shallow lateral 

 lobes, and one at each end ; length 1-185". 



*** End lobe indistinct ; frequently a process 

 or acute angle at the corners of the ter- 

 minal portion. 



E. elegans. Oblong ; ends emarginate, 

 pouting, and rounded ; length 1-890 to 

 1-420". 



Conjugation has been observed in several 

 species ; the sporangia are spherical, with 

 conical tubercles, or acute or obtuse spines. 



BIBL. Ralfs, Brit. Desmid. 78; Raben- 

 horst, Fl. Alg. iii. 179. 



EUCAM'PIA, Ehr. A marine organism, 

 allied to the Desmidiaceae, among which it 

 is placed by Kiitzing, whilst Smith refers it 

 to the Diatomaceae. 



It forms articulated, arcuate or spiral, 

 fasciaeform, microscopic fronds, composed 



of hyaline wedge-shaped frustules, with 

 yellowish granular contents. The joints 

 shrink in drying, and are destroyed by heat. 

 The markings consist of dots. 



E. zodiacus (PI. 50. fig. 10). Frustules 

 with a median excavation on each side ; 

 valves elliptical ; length 1-710". 



E. britannica. Frustules not excavated : 

 length 1-380". 



E. striata. Valves circular ; endochrome 

 green. 



BIBL. Ehrenb. Abh. Berl. Ak. 1839, 125; 

 Kiitzing, Sp. Alg. l$l,Bacillar. pi. 21. fig. 21 ; 

 Smith, Br. Diat. ii. 25 ; Stolterforth, Jn. M. 

 Soc. 1879, ii. 835. 



EUCERTYD'IUM, Ehr. A genus of 

 Polycystina. 



E. ampulla (PI. 39. fig. 25, front view ; 

 fig. 26, under view). 



See POLYCYSTINA. 



EUCHLAN1DOTA, Ehr. A family of 

 Rotatoria. 



Char. Rotatory organ multiple, or divided 

 into more than two lobes ; a carapace pre- 

 sent. 



The carapace forms either a testa or a 

 scutellum ; various appendages are present, 

 representing either straight bristles, curved 

 bristles or hooks, minute horns so-called 

 respiratory tubes or antennae, and in one 

 genus a frontal hood. 



The eleven genera are thus distinguished : 



Eyes absent; foot forked 



Eyes present. 

 Eye single (cervical). 

 Foot styliform. 



Carapace depressed Monostyla. 



prismatic Alastigocerca. 



Foot forked. 



Carapace open beneath Euchlanis. 



closed beneath. 



Carapace with horns Salpina. 



,. without horns Dinocharis. 



Eyes two (frontal). 



Foot styliform Monocerca. 



forked. 



Carapace compressed or prismatic. Colurus. 

 depressed or cylindrical. 



Head without a hood Metopid-ia. 



with a hood Slephanops. 



Eyes four ; foot forked Squamella. 



BIBL. Ehrenb. Inftts. p. 455. 



EU'CHLANIS, Ehr. A genus of Rota- 

 toria, of the family Euchlanidota. 



Char. Eye single, cervical ; foot forked ; 

 carapace cleft or open on the ventral surface. 

 Aquatic. 



Ehrenberg describes six species, to which 

 Gosse adds three. 



E. triquetra (PI. 43. fig. 30; fig. 31, teeth). 

 Carapace very large, with a dorsal crest; 

 foot without setae ; length 1-48". 



