508 DICTYOTACEAE. 



width; the lobes are marked by conspicuous dark slightly curved transverse 

 lines, these forming the boundaries of zones, which are mostly J-i inch broad ; 

 the color of the younger parts is a brownish olive-green, occasionally verging 

 towards red ; the older parts are dark brown, becoming nearly black on drying. 

 More ragged and dissected forms also occur, with lobes or laeiniae scarcely 

 more than J inch broad. This typically West Indian species was first described 

 from Santo Domingo, but what seems to be the same thing occurs also in the 

 Canaries. (Phyc. Bor.-Am. 1876, as Zonaria lobata.) 



Zonaria variegata (Lamour.) Ag. occurs on rocks, Udoteas, Halimedas, 

 and other objects that may be reached by wading at low tide, as at Gibbet 

 Island, Harrington Sound, Castle Harbor, Hungry Bay, and St. David's 

 Island, and is also found washed ashore 'from deeper water, as on South Beach. 

 It is a much smaller, less stalked, less lobed, and less distinctly zonate plant 

 than Z. zonalis. The thallus is semiorbicular or flabelliform, mostly 1-3 

 inches broad, nearly entire or showing a few flabelliform segments ; the 

 margins are subentire or crenate-lobed ; the color is olive, brownish olive, 

 fuscous brown, or now and then reddish. It sometimes suggests a Padina but 

 the apical margins are not inrolled as in that genus. This typically West 

 Indian species has been reported also from the Canaries and elsewhere. 

 Zonaria collaris Ag. is probably a synonym. (Phyc. Bor.-Am. %028.~) 



Padina is a genus of the Dietyotaceae that is represented in Bermuda by 

 three species growing on rocks near the low-tide mark, or in shallow water. 

 The three species have been more or less confused with each other and all 

 have been identified with the Padina pavonia of southern Europe, with which 

 only one of the three, and that the rarest, appears to be identical. The three 

 often resemble each other very much in outward habit. In all, the thallus is 

 distinctly zoned, and, as in nearly all Paclinas, the apical margins are narrowly 

 inrolled. 



Padina Sanctae-Crucis B0rg., which is probably the commonest, has, in 

 Bermuda, a semi-orbicular, fan-shaped, or occasionally reniform thallus, mostly 

 l-3 inches broad, subentire or sparingly divided or lobed, and is conspicuously 

 encrusted with lime on the ventral surface ; when living, it is commonly con- 

 cave in such a fashion as to be a little suggestive of the human ear or of cer- 

 tain bivalve shells; sections, examined microscopically, show that the thallus is 

 only two cells thick except at the extreme base, where it is three cells thick. 

 The tetrasporic sori occur just above every second piliferous line and are pro- 

 vided with an evanescent indusium. (Phyc. Bor.-Am. 2082.*) 



Padina pavonia (L.) Gaill. has been found on Gibbet Island by Hervey 

 (Phyc. Bor.-Am. 2081*). It resembles the preceding but has a more cuneiform 

 thallus or thallus-lobes, the thallus is mostly 3 cells thick, the tetrasporic sori 

 commonly border each side of every second piliferous line, and the indusium 

 is conspicuous and rather persistent. 



A third species [Padina variegata Hauck, Zonaria variegata Kiitz., not 

 Zonaria variegata (Lamour.) Ag.], for which Dr. W. D. Hoyt is soon to pub- 

 lish a valid name, has ultimately a larger thallus than the two preceding, 



