342 



HYDROID^. 



Part IV. 



6th Family. Eudendroid^ Ag. See p. 282. No free Medusae. 

 Eudendrium Ehrenh. — Calamella OJccn. — Thoa Lamx. 



E. ramosum Ehrenh. — Tubularia ramea Dalycll, PL 6. — Northern 



Europe (Linnaeus). 

 E. dispar Ag. — Thoa dispar Ag., Vol. 4, PI. 27, figs. 10-26. — Mas- 

 sachusetts Bay (Agassiz). 

 7th Family. Tubularid^ Johnst. (restricted).'^ 

 Tubularia Linn, (restricted). 



T. indivisa Linn., Dalyell, Pis. 1-4 ; Johnst., Zooph., PI. 3, fig. 1. 



See p. 241. — Northern Europe (Linnaeus). 

 T. Couthouyi Ag., p. 266, PI. 24. — Massachusetts Bay (Agassiz). 

 Thamnocnidia Ag. 



T. coronata Ag. See p. 242. — Tubularia coronata AI)ild. — NoHhern 



Europe (Abildgaard and VanBeneden). 

 T. calamaris Ag. See p. 242. — Tubularia calamaris VanBen. — 



Tubularia gracilis Johnst. — German Ocean (VanBeneden). 

 T. spectabilis Ag., p. 271, PI. 22, figs. \-10. — Boston Bay, Nahant 



(Agassiz). 

 T. tenella Ag., p. 275, Pi. 22, figs. 21-?,^. — Nahant (Agassiz). 

 P a r y p h a Ag. — Pyxidium Leuclc. ? 



P. cristata Ag. — Tubularia cristata Mc Cr. — Charleston (McCrady). 

 P. crocea Ag., p. 249, PI. 23. — Boston Bay (Agassiz). 

 Pyxidium truncatum Leuck., Arch. Nat., 1856, PI. 2, fig. 7. — Nice 

 (Leuckart).^ 

 Ectopleura Ag.^ 



E. Dumortieri Ag. See p. 242. — Tubularia Dumortieri VanBen. — 

 German Ocean (VanBeneden). 



* As here limited, the Tubularidse embrace only 

 those Hydroids the head of which has a wreath 

 of simple coronal tentacles, and a proboscis with 

 simple tentacles around the mouth ; producing either 

 sessile or free njedusa;, more or less one-sided, 

 budding from the floor between the coronal tentacles 

 and the proboscis. 



^ Kijlliker has described a Tubularia which be- 

 longs to the genus Parypha (see p. 242), and may 

 be the parent of Leuckart's Pyxidium. The emi- 

 nent anatomist uses expressions in this description, 

 which require our special attention. What he 



calls sexual organs are unquestionably medusae-buds, 

 and the hollow cone of these organs is the pro- 

 boscis of the medusa. The parts of these so- 

 called sexual capsules are, in fact, homologous to 

 the parts of the free meduste, in all their details ; 

 and this shows them to be distinct individuals, for 

 an organ homologous to a whole animal, in all its 

 parts, would be a singular anomaly. 



' Ectopleura Ag. In this genus are included 

 those species formerly referred to Sarsia, having 

 a short digestive trunk, not provided with movable 

 lips ; and in which the pigment cells of the sen- 



