390 THE AMERICAN NATURALIST. [VoL. XXXV. 
Gonosome : Gonangia more or less oval, sessile, with marginal rim. 
Male gonangia somewhat more slender, and regular in outline. 
Habitat: One of our commonest sertularians, found attached to fucus, 
etc., between tide marks and in tide pools. 
2, S. cornicina McCr. 
Trophosome : Colony very small, composed chiefly of unbranched stems, 
which rarely attain a height of more than % inch. Hydrothecz appearing 
as lateral emarginations with slightly diver- 
gent apertures. Hydranths slender, with 
about. sixteen tentacles. 
Gonosome: Gonangia ? 
The above description is condensed and 
modified from that of McCrady (Proc. 
Elliott Soc., Vol. 1, p. 204). 
3, S. argentea Ell. and Sol. 
Trophosome : Colony of bushy and slightly 
wavy stems, perisarc dark and horny; branch- 
ing, alternate, and somewhat dichotomous. 
Hydrothecz short, urn-shaped, tapering to- 
ward the free and divergent aperture, which 
Fic. 26.— Sertularia pumila Linn. is small and oblique. 
(After Agassiz.) 
Gonosome: Gonangia broad, obovate, 
tapering toward the base; aperture circular, and usually with two 
divergent spines. 
Habitat : Usually from deeper waters, growing on shells, stones, etc., 
sometimes found near tide marks. Recorded from various points along the 
New England coast. 
4, S. cupressina Linn. 
Trophosome : Colony slender, elongated. Stems rather stout and straight, 
alternately branched and dichotomously sub-branching. Hydrothece tubu- 
lar, transparent, somewhat alternate, and adherent throughout most of their 
length, slightly divergent toward the aperture, which is wide and bilabiate. 
Gonosome: Gonangia elongate, tapering toward base, and with promi- 
nent spine at each side of the aperture, which is slightly raised and central. 
Habitat : Less abundant than the former species, though with similar 
distribution. 
Sertularella Gray. 
Generic characters given in above synopsis. 
