roL.3.] Torrey .—Hydroida of the Pacific Coast. 23 



67. Mouth of hydrotheea reaching beyond middle of next one above; 

 hydrothecae crowded, often more than 5 to an internode..H. faleata- 



G7. Hydrothecae flask-shaped, much narrowed distally.H. franciscana 9 

 6S. Hydrotheea alternate, one to an internode Sertularella group 69 



68. Hydrothecae in pairs, one pair to an internode Dynamena group 75 



68. More than two hydrothecae to an internode Thuiaria group 77 



69. Margin of hydrotheea dentate 70 



69. Margin of hydrotheea entire, everted, hydrotheea tubular 



S. halecina (p. 61) 



69. Margin of hydrotheea smooth or bilabiate; hydrothecae distant 



S. nana 



70. Two marginal teeth. Hydrothecae almost uniserial ; branches in 



an apical tuft Sertularella clarki' ; 



0. Three marginal teeth 71 



0. Four marginal teeth 72 



71. Stem slender, hydrothecae distant, narrowing toward orifice, with 



corrugations on side nearest stem S. conica (p 60) 



1. Branches arising within or in place of hydrothecae; margin of 



hydrotheea reduplicate S. dentifera (p. 61) 



1. Branching irregular, proximal half of hydrotheea adnate, distal 



half bent away from stem, narrowing to orifice S. hesperia (p. 63) 



1. Pinnately branched; hydrothecae short, tubular, adnate for half 



their length, opening upward S. pinnata 1 



1. Hydrothecae smooth, tubular, adnate at base only, opening out- 

 ward and upward S. tricuspidata 8 



1. Stem stout, flexuous, hydrothecae well immersed, usually rough- 



ened or corrugated, with wide aperture; gonothecae annulated, or 

 distally spinose, or both S. turgida (p. 64) 



2. Hydrothecae smooth 73 



2. Hydrothecae annulated 74 



3. Stem slender, annulated S. fusiformis (p. 61) 



3. Stem smooth, branching irregular and distant S. polyzonias s 



74. Stem stout, sparsely branched, hydrothecae and gonothecae annu- 

 lated.. S. saccata" 



'4. Stem slender, unbranched, annulated, geniculate 



S. tenella (p. 64) 



5. The two hydrothecae of same pair scarcely in contact. .. S. pumila" 1 



5. The two hydrothecae of same pair usually in contact for at least 



half their length 76 



6. Margin with two prominent teeth S. furcata (p. 66) 



7. Margin of hydrotheea entire S. desmoidis (p. 65) 



77. Outer margin pointed; chitinous point projecting upward from bot- 

 tom o feach hydrotheea; gonotheca top-shaped Thuiaria coei'-' 



77. Margin of hydrotheea bilabiate 85 



77. Margin of hydrotheea with four teeth, operculum of four pieces... . 



Sertularella albida" 



78. Hydrothecae never in more than two rows 79 



78. Hydrothecae in three rows in distal portions of branches, deeply 



immersed Sertu'aria incongrua (p. 69) 



79. Aperture round or transversely oval 80 



79. Aperture pitcher-like, with single operculum; hydrotheea with 



double curve in front Thuiaria elegans'- 



