CODIACEAE. 501 



dichotomous. In its typical condition, C. verticillata is a plant of lagoons 

 and of the mangrove association, being often found attached to the roots of 

 Ehisophora near the low-water mark. Its erect branches may then attain a 

 height of 1-6 inches and the dichotomous ramuli occur in a more or less 

 clearly defined succession of whorls or tufts. 



Family CODIACEAE. 



Avrainvillea nigricans Decaisne, occurs on rocks just below the low- 

 water mark, as at Gibbet Island and Harris Bay. It is spongy and blackish 

 and the flabelliform, cuneiform, or oblong upright part is in the Bermuda 

 specimens mostly only 2 or 3 inches high. Under the compound microscope 

 the filaments of the flabellum are found to be moniliform. (Phyc. Bor.-Am. 

 8171.) 



Avrainvillea longicaulis (Kiitz.) Murr. & Boodle, occurs in the ponds of 

 "Walsingham, where it gets to be more than a foot tall. It here has a long 

 stalk, finally terminated by an irregular flabellum that is sometimes several 

 inches long or broad. In external form, however, this species and A. nigricans 

 often resemble each other closely and the best distinguishing characters are 

 found in the form of the filaments of the flabellum, which in A. longicaulis 

 are commonly cylindric with a strong constriction at the base of each branch. 

 From the Udoteas, the Avrainvilleas are distinguished by their lack of calci- 

 fication, by their softer more spongy texture, and by their blackish or dusky 

 brown color. (Phyc. Bor.-Am. 2170.) 



Udotea Flabellum (Ell. & Soland.) M. A. Howe, is a more or less fan- 

 shaped calcified light yellowish green or dark olive-green plant, mostly 2-10 

 inches high, and showing concentric zonations. The flabellum has a compact 

 firm cortex. Forms occur in which the flabellum is variously lobed and 

 laciniate. The species is rather common in 1-50 feet of water, growing 

 mostly on a sandy or muddy bottom. (Phyc. Bor.-Am. 1914.) 



Udotea conglutinata (Ell. & Soland.) Lamour. is usually a smaller 

 lighter green plant, the flabellum of which is destitute of a highly specialized 

 cortex. Under a hand lens the surface of the flabellum appears spongiose or 

 longitudinally strigose. With a higher magnification each of the flabellum 

 filaments is seen to be enclosed in a porose calcareous sheath. This species 

 has been found on South Beach in Paget by Farlow and at Harris Bay by 

 Hervey. (Phye. Bor.-Am. 1913.) 



Penicillus capitatus Lamarck, the Merman's Shaving Brush, is common, 

 usually on a sandy or muddy bottom in shallow water. It has a subterete and 

 strongly calcified stalk and a commonly subglobose head, the free diehotomous 

 filaments of which are each enclosed in a porose calcareous sheath. The plants 

 are usually from 1 to 9 inches in height. (Phyc. Bor.-Am. 1911 and 1912.) 



Penicillus pyriformis A. & E. S. Gepp, has a more pyriform-obovoid or 

 obconic head and usually a shorter stalk and the filaments of the head are more 

 intertangled. The best distinguishing characteristics are, however, found in 



