Algal Genera Acicularia and Acetabulum 323 



the cohesion in a single mass are the only characters separating 

 Acicularia, as defined by Solms-Laubach, from the genus Ace- 

 tabulum, and while a segregation on this ground is doubtless de- 

 fensible, the propriety of thus using the generic name Acicularia 

 perhaps awaits the further study of the fossil remains on which 

 the genus Acicularia was founded. 



The specimens on which the following observations were made 

 were collected by the writer at Hungry Bay, Bermuda, on June 25, 

 1900. The plants were growing on small stones at about the low 

 tide mark in a shallow creek leading out from a mangrove thicket. 

 Through the kindness of Professors Mobius and Schenck we have 

 been permitted to see the original Brazilian material of Acicularia 

 Schenckii. A careful comparison of this and the Bermudian speci- 

 mens reveals a few slight differences which are not, we believe, of 

 specific significance. The differences are referred to below. Count 

 Solms states that Goebel collected beautiful specimens of this 

 species in Curagoa and that it has been collected also in Martinique 

 and Guadaloupe. But its occurrence now in Bermuda, about a 

 thousand miles farther north, is in itself a point of some little 

 interest. 



2. Descriptive. 



Acicularia Schenckii (Mob.) Solms, Trans. Linn. Soc. Bot. II. 



5 : 33- pl- 3-f- 9> IT > I2 > *4* T S- l8 95- 



Acetabularia Schenckii Mob. Hedwigia, 28: 318-320. pL 10. 



/. 8-12. 1889. 



Green at first, becoming strongly calcified and chalky white 

 with age : disc very nearly flat, solitary, 4-6 mm. in diameter, the 

 margin crenulate ; sporangia 30-42, cuneate, strict, firmly connate 

 at maturity except as to the rounded-obtuse minutely mucronate 

 apex, the free extremities conical when young ; coronal processes 

 mutually free, emarginate or emarginate-bilobed, with or without 

 a transverse invagination, each bearing two caducous polytomous 

 branches or the rudiments or scars thereof ; hypopeltal processes 

 emarginate-bilobed, sometimes twice dichotomous : aplanospores 



too in a sporangium, globose, 66-84 ft in diameter ; the cal- 

 careous massula subcuneate, rounded or somewhat truncate at 



00- 



ty 



entire surface, usually thicker in the vertical plane than in the 

 horizontal (tangential), the radial sides often concave toward the 



