LBPTOMEDUSAE. 



133 



Fam. 3. Perisiphonidae. Hydrocaulus enveloped by peripheral tubes ; the 

 hydrothecae are never adnate and are carried by the axial tube only. Lafoea 

 Lamouroux ; Lictorella Allm. ; Cryptolaria Busk ; Perisiphonia Allm. 



Section 2. Sertularinae. ^ 



Hydrothecae developed from more than one side of the hydrocaulus, to which 

 they are all adnate for a greater or less extent by their sides. 



Fam. 4. Grammaridae. Hydrocaulus consisting of an axial tube which carries 

 the hydrothecae and is sur- 

 rounded by and inseparably 

 coalesced with peripheral tubes 

 without hydrothecae. Hydro- 

 thecae adnate to axial tube. 

 Grammaria Stimpson. 



Fam. 5. Sertularidae. Hy- 

 drothecae in two or more 

 series, adnate to hydrocaulus. 

 Gonophores sessile. Sertularia 

 L. ; Diphasia Agassiz ; Thui- 

 aria Fleming ; Desmoscyphus 

 Allm. ; Hypopyxis Allm. ; 

 Staurotkeca Allm. ; Dictyo- 

 cladium Allm. ; Synthecium 

 Allm. ; Thecocladium Allm. ; 

 Hydrallmania Hincks. 



FIG. 115. Free Medusa of Obelia gelatinosa as yet 

 without gonads ; g otocysts. 



Section 3. Idiinae. 



Hydrothecae adnate to hy- 

 drocaulus. Coenosark divided 

 into segments which form two longitudinal series of intercommunicating cham- 

 bers, each of which communicates with the gastral cavity of a hydranth. 



Fam. 6. Idiidae. Idia Lamouroux. 



Section 4. Plunmlarinae. 



Hydrothecae developed from one side only of the hydrocaulus, to which they 

 are adnate by their sides. Sarcostyles (nematophores) are always present. 



Fam. 7. Plumularidae. Antennularia Lamarck; Sciurella Allm. ; Acanthella 

 Allm. ; Plumularia Lamk. ; Schizotricha Allm. ; Polyplumaria Sars ; Heteroplon 

 Allm. ; Halicornaria Busk ; Azygoplon Allm. ; Streptocaulus Allm. ; Diplochcilus 

 Allm.; Lytocarpus Kirchenpauer ; Acanthocladium Allm.; Cladocarpus Allm.; 

 Aglaophenia Lamouroux. 



The Medusae of this order are arranged by Haeckel as follows : 

 LEPTOMEDUSAE. 



Craspedota partly icifh, partly without, otocysts ; ocelli ywesent or 

 absent ; gonads on radial canals ; budded from polyps of the 

 Campanulariae. 



Fam. 1. Thaumantidae. Radial canals simple, unbranched, without otocysts. 

 Polyp form known only in Laodice (Thaumantaria) calcarata as Thaumantias 

 inconspicua, and in Melicertum campanula as Melicertum campanula. 



