536 XEMASTOMATACEAE. 



Mediterranean specimens referred to this species in their bright red color and 

 in their softer looser cortex, its constituent filaments being more readily 

 separable. 



Nemastoma gelatinosum M. A. Howe, sp. nov. Thallus very soft, gelati- 

 nous, and lubricous, light purplish-vinaceous, forming a subhemispheric or 

 somewhat flattened shrub-like tuft 6-13 cm, high, subterete or here and there 

 complanate, repeatedly (5-9 times) and in general closely subdichotomous, the 

 branching mostly in one plane or occasionally, especially toward the apices, in all 

 directions, often crowded-subpalmate, now and then subpinnately distichous, the 

 branches unequal, mostly 3-6 mm. in diameter or in flattened parts sometimes 

 10 mm. broad, slightly tapering, obtuse or subacute, occasionally terminating 

 in a pair of small subdivaricate teeth about 1 mm. broad; medullary filaments 

 7-12^4 in diameter; cortex of 5 or 6 times di(tri)chotomous submoniliform 

 fastigiate filaments 80-140 /j. long, loosely imbedded in mucus and easily 

 separable, the forkings rather wide-angled, the cells mostly obovoid, those of 

 the surface usually 3-9 /jl X 3-6 fi ; other parts unknown. 



On rocks in about 3 m. of water, in Castle Harbor near Tucker's Town 

 (type, Hoice 316, in herb. X. Y. Bot. Gard.). Also collected in Bermuda by 

 Faxon (in herb. Farlow). Nemastoma gelatinosum may possibly include the 

 plants somewhat doubtfully referred above to PJatoma cyclocolpa, to which it 

 bears much resemblance in structure, but, if so, the species is remarkably 

 protean in habit. N. gelatinosum is a softer, more gelatinous, usually lighter- 

 colored, suffrutescent plant, with all parts predominantly subterete, while the 

 so-called PJatoma cyclocolpa is a plane membranous plant, with a marginal 

 fringe of lobules or crenations. In its mucosity and its tenuity when pressed 

 and dried, N. gelatinosum suggests the Mauritian N. coliforme J. Ag., to 

 which it seems closely related, but it manifestly differs from this in its com- 

 pact suffrutescent habit. Apparently endemic. 



Family SQUAMARIACEAE. 



Peyssonnelia rubra (Grev.) J. Ag. forms dark red or pinkish red, reni- 

 form or cuneate-orbicular, thin and rather fragile, loosely attached, mem- 

 branous, often lobed crusts -i-l inch broad, on the bases of the larger algae and 

 Gorgonians in deep water or on rocks near low-water mark in littoral caverns. 

 The ventral surface is whitened with lime, mostly coating a very short 

 tomentum of rhizoids. iSuperposed imbricated lobes are often developed. The 

 cells of the upper surface, viewed from above, are polygonal, in regular 

 radial lines. In a cave at Gravelly Bay (Collins). 



Other species of the genus and family doubtless occur. The Squamari- 

 aceae in general have a horizontally expanded crustaceous thallus, often more 

 or less calcified. They may usually be distinguished superficially from the 

 crustaceous forms of the Corallinaceae by the lighter calcification, the deeper 

 red or yellowish color, the more obvious margins, and by the absence of definite 

 cavities or conceptacles in which the reproductive organs occur, such organs 

 being either scattered or aggregated in superficial sori or nemathecia. 



Family CORALLINACEAE. 



The members of this family show a great variety in outward form, but the 

 known Bermudian representatives of the family agree in having a strongly 



