Vou. 2] Torrey.—Hydroids of the San Diego Region. 
KEY TO FAMILIES, GENERA AND SPECIES. 
. No true hydrothecae or gonangia .......... .......... ........ Gymnoblastea 
1. True hydrotheeae and gonangia present.........._..... Calyptoblastea 
2. Tentacles in proximal and distal sets; hydranth abruptly set off 
OTHE SUC Litem meres Ar cee tv eel Ei ee a Pennariidae 
Pealentaclessimuonercirclet, filufomm eee sc ue es 
3. Solitary nutritive polyp, rooted in sand; perisare rudimentary ......... 
sogicna Cucest eeepc ee Be ST ne ES eee aa Corymorpha 
3. Several anaes polyps from common stolon; perisare well 
developedssconophores! feds ee eee Tubularia 
4. Not more than 30 proximal tentacles; doneohores without tentacles 
Ee REE re PRA 5 CoE INE ly RAR SO ee A Deen, C. palma (p. 9) 
5. About 25 proximal tentacles; gonophores with 6-10 flattened pro- 
OSS OS UME Maree Pest Stas rene SOS NRE Re See TN ene T. crocea (p. 10) 
6. Colony encrusting; hydranths clavate; spiral zooids; spines on 
hydrorhiza _..... get eee ae Be EN Nea Brae Hydractiniidae, Hydractinia 
Gr © ol Omiyanon Chia aerate. rat 6 te ae ee Sp AP Oe DLAONE LE Sent os 
7. Sterile hydranths with 6-10 tentacles; blastystyles sai knoblike 
Gembaclesy ete ete ea pte ea eee NE ote le ok H. californica (p. 19) 
8. Proboscis trumpet sisal. lonychiaivansm 1aVONe THOUSNUEO WAC es ene ee 
Weal rn erent Need Ss. ba AS i wy Ae Eudendriidae, Eudendrium 
8. Proboscis conical; hydranth fusiform .............. .......... Bougainvilliidae 
9, Stem and principle branches polysiphonie............... E. rameum (p. 8) 
9. Stem polysiphonie at base only; branches simple... 
shy jal otek eng eee R, LE ee ee OE LN ER ne ad . E. ramosum (p. 8) 
ORR ONOPHOTES xe ClSPOROSACS =e i ane eee eee eee Bimeria 
10. Gonophores liberated as medusae, with four pairs of tentacles... 
ee fe mg te ero ie NL Gi Nur eB ine ton LU ee as EN Bougainvillia 
11. Stems simple, only partially annulated; hydranth with 10-12 
LOMUACIE Sentence ence ey tne Marra eelomte Lie rr eke B. gracilis (p. 6) 
12. Stem and branches without annulae, often twined about each other.. 
serie ot Ta aR oo oer eae EN aE IE EE B. glorietta (p. 7) 
Sp eNemat OplOTesy Sos emit eye ey ets ee ee ee ee en eee 
13. Nematophores present; hydrothecae sessile, on one side of stem or 
Joram cle szomiliya emer st ted eo wen ays pear ieeeeee ee Plumulariidae 
14. Hydrothecae with definite basal septa; gonangia not aggregated 
14. Hydrothecae without definite basal septa, tubular; smooth margined; 
Cone Cdayame rer ate den hers eee eee ele A yy — latoeidae 
15. Hydrothecae much wider than deep ......... .. Use ESS ety see Haleciidae 
15. Hydrothecae campanulate, usually deeper than wide, never adnate 
TO POU GEN CURA ce sae casey tine eo a Egle Campanulariidae 
15. Hydrotheeae sessile, adnate or immersed, in 2 to 6 rows. Sertulariidae 
16, Gonangia with sporosaes ..............--.--....- ESO ee Halecium 
(PMOLOUI NOt ASCIC]OG te eenem ree = eth nie ety ee oe Re meee e A Deere 
17. Stem fascicled; ultimate branches gontealnres H. washingtoni Ge. 11) 
. Annulated; hydrathecae about half as deep as broad, margin everted 
Re es de ke CM h ee ee ein eee et eh LS eee H. annulatum (p. 10) 
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