ULVACE^E. 131 



Scot, ii., 91. Johnst. Fl. Benv. ii ., 249. Hull, Br. Fl. 311. 

 Abbot Fl. Bedf. 273. With. AIT. iv., 125. 



Scytosiphon intestinalis. Gray, AIT. i., 315. 



Enteromorplia lacustris. Hass. Trans. Linn. Soc. 



Fistularia intestinalis. Grev. Fl. Edin. 300. Fl. Devon, 

 ii., 57. 



In ditches, chiefly in brackish water. 



This exceedingly variable species has many forms or varieties to which 

 names have been given, one of which by rupture of the apex, is funnel- 

 shaped (var. CornucopicB), others are more or less thread-like, and others 

 inflated and bullate. Root a minute scutate disc. Frond from a few 

 inches to one or more feet in length, and from a line to three or four 

 inches, or more, in diameter; tubular, obtuse, tapering at base to little 

 more than the diameter of hog's bristle, gradually becoming inflated 

 upwards, and in old age often swelling out into a large membranous 

 bag, which is variously cusped and curled. Sometimes the whole frond 

 is compressed and very much crisped ; substance thin and membranous, 

 but not gelatinous, not closely adhering to paper in drying. Colour 

 varying from a transparent yellowish green to a dull grass green; in old 

 age and decay fading to a dirty white. Under the microscope a portion 

 of the frond exhibits the appearance of a transparent membrane covered 

 with green unequal angular cells. Harvey. 



It occurs on the sea shore, in tidal rivers, and ditches connected with 

 them, whether salt, brackish, or freshwater, sometimes at a considerable 

 distance from, the sea. In this respect it differs from, Enteromorplia 

 compressa, which is nut found in fresh water, and has therefore no claim 

 to be inserted in the present work. 



Plate LI. Jigs. 1, 2. Small fronds of Ent. intestinalis, natural size. 

 Fig. 3, the variety Cornucopia, nat. size. Fig. 4, cells X 400. Fig. 5, 

 zoogonidia. 



'o* 



GENUS 56. MONOSTROIKA. T/tur. (1854.) 



Frond plane or saccate, simple or torn and lobate, composed 

 of one stratum of cells, cells somewhat rounded (sometimes 

 quaternate) immersed in a homogenous membrane. Thuret,Note 

 sur la synonymie des Ulva, fyc. 



This genus was formerly included in Ulra, from which it was separated 

 by Thuret. See also Monograph of Monostroma, by Prof. V. Wittrock. 

 The majority of species are marine. 



Monostroma laceratum. Thur. Note sur Ulv. 



Thallus membranaceous, at length free, thin and flaccid, pallid 

 green, of irregular form, rugose, margin plane and eroded, or 

 crisped (*04-'05 mm. thick) ; cells rounded, twin, ternate, or 

 quaternate, disposed loosely in the intercellular substance, in 

 transverse section of the thallus oval (017-'023 mm. high), 

 chlorophyllose body central, of the same form as the cell, of 

 which it occupies about one-half. Wittr. J/o/?. Monostr., p. 

 80,*. I,/ 2. 



Plate LI., fig. 6. Portion of frond X 200. Fig. 7, section of frond 

 X 200 diam. 



