l I 2 



in diameter (without papillae), la te rail) coherent in one plane by 



numerous approximated obtuse or mamillatel) apiculate 



conical pap I in single i>r doublé rows along the fronl and back of the filament, 



ing pair-wi posite one another; on the basal filaments they form close 



whorls lii-r>- .nul there, and 01 onall) ari forked or geminate. Supra-dichotomial constrictions 



uneven. • 



:i il. subsp. 



i Expedition. Stat. 285. South Coast of Timor. 34 meters. Lithothamnion bottom ! 



int 5 cm. high. Frond 4.5 cm. long, 2 cm. wide, zonate. Differs from the type in 



much shorter and more obtuse papillae, often inconspicuous, and at somewhat wider 



intervals on the filaments of the frond. The frond filaments are about 30^ in diam. above 



and about 55 y. at base, where the) are irregularly beset with short fibulae 30 — 70 7. long. 



fig. 41). [Figs. 39—42 . 



U. papillosa (fig. 37), which in genera! habit resembles U.javensis (fig. $6) is one of the 

 simplest of the genus. Smal! specimens were found preserved in spirit together with equally small 

 plants of U.javensis, trom which species U. papillosa may usually be distinguished, even before 

 decalcification, by its opaque and perforated appearance (fig. 20) when seen under the micros- 

 cope. W'hen decalcified and teased out, the filaments composing the frond are seen to be 

 papil the papillae being arranged for the most part in single or doublé opposite 



rows on front and back of the frond. They vary in shape even in the same filament, being 

 usually either obtusely conical or mamillatel)- apiculate, usually simple, but occasionally geminate 

 near the base of the plant; sometimes also they are arranged in whorls on the basal filaments 

 or on the stipes of the proliferations (fig. 38). These whorls or subwhorls and opposite pairs 

 of papillae are interesting in view óf the normal arrangement of the lateral appendages in U. 

 verticillosa (fig. 23) or U. Wilsoni (fig. 38). In subsp. subpapillata (fig. 39) the papillae are 

 low, broad, inconspicuous bosses on the upper filaments (fig. 42); near the base (figs. 40, 111 

 they are obvious and long (fibulae). The function of the papillae appears to be either to 

 maintain a plentiful and easy communication by osmosis between the interior of the hlament 

 and the circumambient sea-water, or to permit of a readier access of light into the cell-cavity 

 which is rendered dark by the thickness of the calcareous deposit which coats the frond (see 

 pp. 5 and 102, 103). The papillae, reaching to the surface of the calcareous coating appear 

 translucent in the opaque frond (fig. 20). 



In mature plants, the primary filament becomes hidden bj a coverinij; of descendin^ 

 rhizoids or prolonged outgrowths of the papillae (fig. 37). The older the plant, the thicker 

 the covering, just as in U. glaucescens \ but in U. glaucescens there is an additional tomentos 



of "fibulae" (compare top of fig. 43), which conceal and bind together the component 

 filaments of the stipes, and extend over the bas.- of the flabellum. Such "fibulae" are verj 

 in U. papillosa (type), being in fact merely elongate papillae. 



Th ubpapillata (fig. 39) is described from a single specimen only, which was 



