Foslie and Howe : New coralline algae 



579 



Lithophyllum Antillarum Fosl. & Howe, sp. nov. 



Thallus grayish-pink or decolorate when living, becoming 

 pallid or greenish-pallescent on drying, forming often somewhat 

 columnar rather flat-topped masses 10-30 cm. high and 8-20 cm. 

 broad ; branches much fused, forming in the basal parts an almost 

 solid mass with more or less lacunae, the irregular and somewhat 

 daedaleoid anastomoses extending nearly to the irregularly pyram- 

 idal, somewhat prismatic, subconical, compressed or occasionally 

 subterete, often truncate or retuse apices, the free portions mostly 



5-25 mm. broad and 3-12 mm. thick, often enlarging upward, 

 the interstices commonly tubular or irregularly infundibuliform ; 

 surface smooth or subpulverulent, or, especially at the sides, 

 minutely corrugated or rugulose; medullary hypothallic cells 

 7-18 /xx 7-10 fi, sometimes forming (in a longitudinal section) 

 irregularly alternating rows of one short and two long cells ; peri- 

 thallic cells subquadrate or roundish, 7—10// in diameter; short 

 rows of larger cells (20-33 t 1 x 14-20 f*) occurring here and there 

 in both medulla and perithallium : conceptacles of sporangia con- 



vex, but little prominent, 1 50-300// in diameter: sporangia 4- 



parted, 38 



0-40 



plates 



Growing at low-water mark on a coral reef at Flamingo Bay, 



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Figure 2.. Lithophyllum Antillarum ; a, portion of surface with tetrasporangial 



■ 



conceptacles, X 5 5 h portion of a radio- vertical section, showing row of enlarged cells 

 X 232 (the cells should be more rounded at the angles, as indicated in photomicro- 

 graph, plate 26) ; c f tetraspores, X I S°* 



Lithophyllum Antillarum is evidently a reef-builder. In general 

 habit it bears some resemblance to coarse forms of Lithophyllum 

 africanum Fosl. (Cape Verde) and to well-developed conditions of 

 Lithophyllum craspedium Fosl., a species originally described from 

 specimens brought from Funafuti and since discovered in the 

 Maldives (see Fauna and Geography of the Maldive and Laccadive 



/• 



It is perhaps the more closely 



related to the latter species, agreeing essentially in structure even 

 to the possession of the peculiar short rows of enlarged cells 



