BY A. ti. S. LUCAS. 55 



Viva lactuca^L. — Ouv common Ulva, which I take to be U. 

 lactnca, is, when only 2 mm. wide, a flat or gently waved mem- 

 brane. I have never seen any appearance of a tube or horn. 

 Very old individuals develop, in the basal part of the frond, an 

 anterior layer which gives to it a much greater thickness and 

 solidity. I append drawings of sections of this basal dark green 

 portion, which, if seen alone and reaching some inches in dimen- 

 sions, has the appearance of a totally different plant(Plate v.). 



The following seem to be new species. 



NlTOPHYLLUM SINUOSUM, Sp.n. 



(Plates ii.-iii.) 



Fronde breviter stipata, tenue membranacea, avenia, circum- 

 scriptione ovali, densissime circumcirca lobata etundulata; stipite 

 cuneato ad 6 vel 7 mm. longo, mox evanescente; margine integer- 

 rimo in breves sublineares lobos egrediente, apicibus loborum 

 obtusis fere rectilinearibus ; cystocarpiis rotundatis 1 mm. 

 diametro metientibus, numerosis in media regione frondis, 

 angusta pallidiori zona concentrice cinctis; soris oblongis, axi 

 majore in marginem frondis verso, 2 mm. longo, per totam super- 

 ticiem frondis superioris, zona satis lata prope marginem excepta, 

 sparsis. Magnitudo frondis maxime variabilis, usque ad 35 cm. 

 x 20 cm. Lacinine rarius visse. Color pulchre roseus. 



A handsome species belonging to the same Group as the 

 Atlantic iV. 2Mnct<itum(St<ickh. ) Grev., and iV r . crispatum(Kiietz.) 

 J.Ag., which appears to be its representative on both sides of 

 Bass Straits. It differs from both in the general outline, being 

 broad rather than long, and the lobes being short and square- 

 edged. It is of a rich carmine when fullest coloured. This colour 

 changes to orange after a few hours' standing in seawater, but 

 returns on drying. The substance is thin and membranaceous, 

 and the fronds adhere most closely to paper. 



I have found it only in Botany Bay, where it grows in a few 

 fathoms on the leaves of Zoster a and C ymodocea. It may be 

 obtained in fruit of both kinds, on different individuals, in any 



