Tin: MARINE ALG.E OF XEW ENGLAND. 63 



t^CVTOSlPllOX, (Ag.) Thuret. 

 (rroin (jKVTo^, a whip, an<l m6ijv, a tulu'.) 



Froiuls simple, oyliiulrical, usually constricted at intervals, hollow, 

 cortex of small colored cells, inner layer of vertically elongated, color- 

 less cells: sporangia as in PhyUitis ; parapliyses single-celled, oblong- 

 obovate, interspersed among the sporangia. 



The prosont gonus is fonndod on the Chorda lomoitaria of older writers. The gonns 

 Sct/tosiphon, as proposed by A,i;ardh, incliuUMl botli ('. lomctituria and C. filiim. Tho 

 latter speries, which is still kept in the Lieniis Chorda by most writers, has tho surface 

 of tho frond covered with club-shaped parapliyses, between which are situated tho 

 oval unilocular sporangia. In S. lomcntarins tho bodies called parapliyses are only oc- 

 casionally found, and their real nature is a little uncertain. Both Hornet an<l Ares- 

 choug consider them to bo paraphyses, and tho latter has figured them in Observa- 

 tiones PhyeologiciD, Part III, PI. 2, Fig. 1. As at present understood, Scytosiphon differs 

 from Phyllitis only in tho fact that the frond is tubular instead of membranous, and iu 

 the presence of paraphyses, which have not yet been found iu PhyUitin. 



S. LOMENTARius, Ag. {Chorda Jomentaria^ Lyngb.; Pliyc. Urit., PI. 

 285. — Chorda filum var. lomentaria, Kiitz., Spec. Alg.) 



Fronds gregarious, three to eighteen inches long, attached by a disk- 

 like base, shortly stipitate, expanding into a hollow tube, from a quarter 

 of an inch to an inch in diameter, at first cylindrical, afterwards con- 

 stricted at intervals. 



Very common on stones between tide-marks; found nearly all over 



the world. 



A species easily recognized, except when quite young, by its tubular and constricted 

 frou<l, but chietly interesting iu consequence of the smaller species of algio which grow 

 apon it. At Eastpjrt a very largo form is found, nearly an inch iu diameter, and 

 much twisted. 



Family PUXCTARIE^. 



Fronds uubranching, forming expanded membranes or cylinders; 

 fructification in spots (sori) on the surface of the fronds; plurilocular 

 sporangia ellipsoidal, composed of few cells ; unilocular sporangia sphe- 

 roidal. 



PUXCTARIA, Grev. 



{Vrom punctum, a point, referring to the dots formed by the sporangia and hairs.) 



Fronds olive-brown, simple, membranaceous, attached by a discoidal 

 base, composed of several (2-0) layers of cuboidal cells of about the same 

 <limensions in all parts of the fronds; unilocular si>orangia immersed 

 in tho frond, collected in spots, spherical-cuboid, formed from the su- 

 perficial cells; plurilocular sporangia collected in spots, immersed ex- 



