18 University of California Publications. 



KEY TO THE HYDROIDA OF THE WESTERN COAST OF 

 NORTH AMERICA.* 



1. No true hydrothecae or gonangia Gymnoblastea 2 



1. True hydrothecae and gonangia present Calyptoblastea 25 



2. Tentacles in proximal and distal sets Pennariidae 3 



2. Filiform tentacles in one whorl 8 



2. Tentacles scattered 20 



3. A single nutritive polyp, rooted in the sand; perisarc rudimentary.. 



Corymorpha 4 



3. Several nutritive polyps from a common hydrorhiza Tubularia 5 



4. About 40 prox. tentacles; body a coral red C. (Rhizonema) carnea 1 



4. Not more than 30 prox. tentacles; stem colorless. ..C. palma (p. 37) 



5. Gonophores with laterally compressed processes 6 



5. Gonophores with conical or tentaculate processes 7 



5. Gonophores with conspicuous radial canals; no processes 



T. indivisa 1 



6. With 4 processes, 32-34 proximal and 50-60 distal tentacles 



.. T. borealis 1 



6. With 6-10 processes and 25 proximal tentacles .... T. crocea (p. 4:: i 



7. 4 tentaculiform processes on female gonophore, as long as gono- 



phore; proximal tents. 22-25 T. marina (p. 46) 



7. 3-5 tentaculiform processes on gonophores, half as long as gono- 

 phores; proximal tents. 40-50 T. harrimani 2 



7. Processes conical; proximal tents. 18-20 T. larynx 3 



7. Proximal tents. 30-40 T. tubularoides 4 



8. Hydranths of two sorts; large sterile and small fertile, each with 



elavate proboscis; spiral zooids: hydrorhiza encrusting, with 



tabular spines Hydractiniidae 



Hydraetinia milleri (p. 34) 



8. Hydranths of one sort 9 



9. Proboscis trumpet -shaped Eudendriidae 



Eudendrium 10 



9. Proboscis conical Bougainvilliidae 13 



10. Hydrocaulus annulated throughout 11 



10. Hydrocaulus not annuluated throughout 12 



11. Height of colony 2 inches or less; female gonophores usually 



without tentacles E. vaginattim- 



11. Height of colony 4-5 inches; female gonophores with tentacles 



E. californicum (p. 32) 



12. Stem and principal branches polysiphonic E. rameum (p. 33) 



' s.n t' the species in the key are described in this paper, others in papers 



mentioned in their several synonymies ; descriptions of the rest may be found in 

 the papers to which the indices after the specific names refer, which have been 

 selected with especial reference to their at ssibility. 



