570 Howe: Phycological studies 



apices : filaments more or less fuscous in the older parts, some- 

 times bright-green in the younger ; filaments of the cortex laby- 

 rinthine, lightly torulose when young, the ultimate branches in 

 older parts 6-11// in diameter, finally subhyaline ; filaments of 

 medulla cylindrical or lightly and irregularly torulose, 30-75 /^ in 

 diameter, slightly or not at all constricted just above a dichotomy, 

 covered by cortex at apices or rarely protruding : stipe similar to 

 the capitulum in structure, its cortex a little thicker and firmer. 



[Plate 25 ; plate 26, figures i 1-20.] 



Rare and local in the Bahama Islands, on sandy or muddy 

 bottom in 2-10 dm. of water (low tide) : 7to. 40 jg, type (in a 

 tidal pond, Georgetown, Great Exuma, 24 February 1905, 

 M.A.H.) ; no. jo8i (south shore of New Providence, 10 April 

 1904 — -a single specimen). 



Besides the single specimen collected on the shores of New 

 Providence, we have thus far met with this remarkable plant on 

 only one occasion, when several hundreds were found growing as- 

 sociated with two species of Penicillus in a small area in an inland 

 pond which had been connected with the sea by an artificial canal. 

 They seemed here to be in all stages of development, but un- 

 fortunately we have been unable to find in them anything that 

 could be taken with confidence to be reproductive bodies. There 

 are often, lying on and among the threads of the cortex, ovoid or 

 subglobose bodies 40-50/^ in diameter, w^ith densely granular 

 contents, much resembling the supposed reproductive bodies 

 figured by Kiitzing * for his RJiipozonium lacimdatum {Udotea 

 Dcsfontainii) ; but these seem to be always free and unattached, 

 their contents are of a little different green, and we believe that 

 they represent an independent organism. 



While the plant is uncalcified in the ordinary sense of the term, 

 the stipe or its base is commonly infiltrated with multitudes of 

 minute crystals which lie free in irregular clusters among the fila- 



ments, particularly of the cortex. When a piece of the stipe is 

 dissected in a drop of water they often wash out in such numbers 

 as to give a milky appearance to the water. The crystals dissolve 

 with the evolution of gas on the application of acetic acid and are 

 taken to be calcium carbonate. 



The cortex is formed by branches originating subdichoto- 



*Phyc. Gen.//. 42. IH.f. 2. 1843. 



