THE ALC YON ARIA OF PORTO RICO. 
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7. Sclerisis. Colony upright, branched from internodes. Axis made up of short, disk-shaped, horny 
nodes and long, finely furrowed calcareous internodes. Calyces bell-shaped. Ccenenchyma 
very thin, without spicules. Spicules of calyces are larger, curved, and spinose. 
11. Isis. Colony branched. Polyps wholly retractile within ccenenchyma. Coenenchyma thick. 
Spicules radiately stellate with 6, 8, or 12 rough warts. 
Family VII. PRIMNOlIhC 
Although this family has a wide distribution, only four genera seem to have been reported from 
the north Atlantic along the American coasts. 
1. Callozostron Wright. 
2. Calyptrophora Gray, emend. W. & S. 
3. Primnoa Lamouroux. 
4. Stachyodes Wright & Studer. 
5. Calypterinus Wright & Studer. 
6. Stenetta Gray. 
7. Thouarella Gray, emend. II'. & S. 
8. Arnphilaphis Wright & Studer. 
9. Plumarella Gray, emend. 
10. Primnoella Gray, emend. Studer. 
11. Caligorgia Gray, emend. Studer. 
12. Primnoides Wright & Studer. 
3. Primnoa. Colony a single stalk or branched dichotomously or forming a bipinnate plume. Axis 
horny, calcified. Polyps on calcife.'ous papillse, club-shaped or scale-like, scattered irregu- 
larly. Spicules small, scoop-shaped in superficial layer. 
6. Stenella. Colony feebly or irregularly and much branched. Axis hard, horny in young speci- 
mens, often highly iridescent. Polyps large and prominent, in whorls of 2-4, opposite. 
Ccenenchyma thin. Spicules large, disk-shaped, often concave with turned-up edges. 
9. Plumarella. Colony upright, branched in one plane, fan-shaped. Axis brittle, calcareous. 
Polyps generally small, cylindrical; in alternating series, usually much separated. Ccen- 
enchyma thin, with two layers of calcareous scales. Spicules thin, cycloid scales with 
central nucleus, prominences small, edge finely toothed. 
11. Caligorgia. Colony ramified, mostly in one plane. Polyp calyces cylindrical or club-shaped, 
irregularly distributed on stem. Ccenenchyma thin, white, containing two layers of 
spicules. Calyx scales fan-shaped, warty, with ribs, arranged fan-like, which project as 
spines from upper edge. 
Family VIII. 
1. Acanthogorgia Gray & Verrill. 
2. Hypnogorgia, Duch. & Mich. 
3. Paramuricea Kolliker & Verrill. 
4. Muriceides Wright & Studer. 
5. Anthomuricea Wright & Studer. 
6. Clematissa Wright & Studer. 
7. Villogorgia Duch . & Mich., Ridley. 
8. Anthogorgia Verrill. 
9. Menella Gray. 
10. Plaeogorgia Wright & Studer. 
11. Echinomuricea Verrill. 
12. Echinogorgia Kolliker. 
MU K I C El DyE. 
13. Menacella Gray & Ridley. 
14. Heterogorgia Verrill. 
15. Aslrogorgia Verrill. 
16. Bebryce de Phillipi. 
17. Acamplogorgia Wright & Studer. 
18. Thesea Duch. & Mich. 
19. Acts Duch. & Mich. 
20. Elasmogorgia Wright & Studer. 
21. Muricella Verrill. 
22. Eumuricea Verrill. 
23. Muricea auct. emend. Verrill. 
1. Acanthogorgia. Colony branching. Axis horny and fibrous. Polyp calyces elongated, expanded 
toward mouth, disposed irregularly. Anterior portion of polyp slightly retractile. Ccenen- 
chyma thin. Spicules spindle-shaped and form large, beautiful extensions on polyp cups. 
2. Hypnogorgia. Colony upright and branched. Branches pendulous. Axis horny and fibrous. 
Polyp calyces attached by inner surface to the axis of growth; operculum elevated and 
conical. Polyps on two sides of axis ojiposite or alternate. Spicules are long spindles. 
3. Paramuricea. Colony generally large, upright, for the most part strongly branched in one plane. 
Axis horny, soft, flexible, translucent, generally flattened on thinner branches. Polyps 
short, cylindrical or verruciform, surrounded by short projecting spicules. Polyps dis- 
posed irregularly, generally three or four at ends of thickened branches, facing in dif- 
ferent directions, none being exactly terminal. Ccenenchyma not very thick. Spicules 
are spiny needles, sometimes dentate, straight, curved, or bent at an angle. 
