276 BULLETIN OF THE UNITED STATES FISH COMMISSION. 
6. Clematissa. Colony branched in one plane. Terminal branches long, their apices being thick- 
ened and knob-like. Axis horny, soft, and flexible. Calyces bluntly conical and rise 
upright from stem and branches. Polyps disposed in short spirals on stem and branches. 
Termination of branch always formed by a polyp. Coenenchyma thick, rough, and 
opaque. Spicules of coenenchyma stout, usually thickened, with knob-like termination. 
Spicules of polyp spiny, club-like, thickened at one end. 
7. Villogorgia. Colony branched in one plane. Branches sometimes anastomose. Axis horny. 
Polyps cylindrical, perpendicular to stem. Coenenchyma thin. Spicules of coenenchyma 
4-8 rayed stars with a few spindles. Spicules of polyps tripartite. 
10. Placogorgia. Colony upright, branched in one plane. Axis horny and flexible. Polyps short, 
cylindrical, and flattened on oral aspect, disposed in narrow spirals. Coennchyma thick. 
Spicules of polyp broad, warty, or thorny plates. Spicules of coenenchyma warty spindles, 
often bent on long axis. 
18. Thesea. Colony upright and branched, with a horny and calcareous axis. Polyps are slightly 
projecting and disposed on either side of flattened branches. Spicules are large, warty, 
scoop-shaped; superficial spindles with large warty knobs. 
19. Acis. Colony branched in one plane. Branches of same thickness throughout. Axis horny. 
Polyps small and placed at long intervals on sides of branches and twigs. Coenenchyma 
a single layer of large spindles. Spicules are extraordinarily large, smooth or warty 
spindles with scales and disks on the polyps. 
22. Eumurtcea. Colony branched. Polyps tubular warts, exhibiting an 8-rayed figure when retracted. 
Spicules elongated, sharp-pointed spindles. 
23. Muricea. Colony branched. Axis horny. Polyps cylindrical, calciferous, cup edges bilabiate 
or circular, disposed irregularly. Coenenchyma thick. Spicules short, thick, spiny and 
warty spindles and clubs. 
Family IX. PLEXAURILLE. 
1. Eunicea Lamouroux. 4. Plexaurella Kolliker. 7. Psammogorgia Verrill. 
2. Plexaura Lamouroux. 5. Pseudoplexaura Wright & Studer. 8. Eunicella Verrill. 
3. Plexauroides Wright & Studer. 6. Euplexaura. Verrill. 9. Platygorgia Studer. 
1. Eunicea. Colony arborescent, trunks cylindrical, branches free, not forming broad plates. Axis 
horny. Polyp cup edges bilobed or crenate. Polyps disposed over whole surface of 
colony on verruciform or papilliform, rather prominent tubercles. Coenenchyma thick 
or moderately so. Spicules leaf-like or thorny clubs. On inside large warty spindles and 
smaller spindles, either of which may be red, violet, or colorless. 
2. Plexaura. Colony arborescent, trunks cylindrical and free. Axis horny. Polyps scattered over 
whole surface of colony, sunken entirely or nearly so into coenenchyma. Cup edges 
smooth or slightly crenate. Coenenchyma very thick and corky. Spicules are club- 
shaped or spinose spindles. 
4. Plexaurella. Colony arborescent. Trunks cylindrical. Axis horny and calcareous. Branches 
free. Polyps as in Plexaura. Coenenchyma usually very thick, thin in P. phillipienm 
Wright & Studer. Spicules are tripartite and quadripartite and simple and leafy clubs. 
5. Pseudoplexaura. Colony feebly branched. Axis horny, with central calcareous portion. Polyps 
close together in a somewhat close spiral, completely retractile. Coenenchyma thick; 
outer layer soft and friable, inner layer contains numerous light purple or violet irregu- 
larly stellate spicules. Spicules of outer layer are spiny spindles with numerous pink 
stars and a few leafy clubs. 
6. Euplexaura. Colony closely resembles Plexaura. Polyps are larger, numerous, and completely 
retractile. Coenenchyma dense and granular. Spicules for the most part short, stout, 
blunt, warty spindles of rather small size, with a few small double spindles and rarely 
small irregular crosses. 
7. Psammogorgia. Colony upright, branched. Axis horny. Polyps scattered over surface, level 
with it or projecting in form of roundish warts. Coenenchyma moderately thick. Surface 
finely granular, with small rough spicules. Spicules are short, thick, spiny, and warty 
spindles and warty clubs. 
