94 Introduction to Animal Morphology. 



an extension of the endotheca protfuded as a pouch 

 through the summit of the gonangium). Gonothyraea. 

 has, above the opercular summit of the gonangium,. 

 two pedicellate, spherical, medusiform gonophores 

 (meconidia), with 8-20 circumoral tentacles and radial 

 canals. 



This includes the following families : — 



I. Campanularidse — with terminal, seldom stalked, oper- 

 culate hydrothecse ; hypostome trumpet-like ; blastochemes: 

 (Eucope, Obelia) or sporosacs (Campanularia, Clytia, 

 Hincksia, Laomedea). 2. Campanulinidae — hydrothecae ovate, 

 operculate ; polypites cylindrical ; hypostome small, conical ; 

 blastochemes(Campanulina, Calycella). 3. Leptoscyphidae — 

 hydrothecse oval ; the ocellated gonochemes are known as; 

 Lizzia, ex. Leptoscyphus. 4. ^quoridas — hydrothecae oper- 

 culate, the lid of converging lanceolate segments ; blasto- 

 chemes discoidal, with (Mesonema, &c.) or without oraE 

 tentacles (/Equorea), and with many radial canals. Stomo- 

 brachium sometimes undergoes fission, and has fine retiform 

 canals in the muscular lining of the sub-umbrella ( Wright).. 

 5. Lafoeidae — hydrothecae tubular ; polypites cylindrical ; pro- 

 boscis conical, ex. Lafoea. 6. Trachydridae — hydrothecae 

 rudimental; polypites cylindrical; proboscis extensile, conical. 

 7, Thaumantiadae — hydrothecae non-operculate ; hypostome- 

 trumpet-like ; blastochemes, with shallow stomachs ; tentacles, 

 often numerous (200 in Tiaropsis), or dissimilar. 8. Cop- 

 piniadse — hydrothecas united by an encrusting cellular mass. 

 9. Lineolaridae — hydrothecae sessile, tubular, with oviform, 

 sessile gonangia. 10. Sertulariadae — sea-firs; hydrothecae: 

 sessile, inserted on the stems and branches of the hydro- 

 caulus ; polypites retractile, with one circlet of filiform ten- 

 tacles ; sporosacs fixed. 11. Haleciidae — hydrothecae none,, 

 or rudimental, biserial, sub-sessile, joined to a lateral process-, 

 from the stem ; polypites not, or partly, retractile ; blasto- 

 styles, bearing the sex-products (not in sporosacs), develop, 

 within modified single internodes of the stem (pseudogonan- 

 gia), each of which bears a hydranth i^Allman), ex. Halecium. 

 12. Plumularidae — hydrocaulus bearing, besides the ordinary 



