loo hitrodudion to Animal Morphology. 



There are seven families, viz. : — 



I, Apolemiadse — possessing nectocalyces ; hydrophyllia„ 

 with the other organs, arranged in groups at intervals along 

 the filiform ccenosarc ; pneumatocyst small ; tentacles with 

 no lateral branches; gonophore. free, ex. Apolemia. 2. Ste- 

 phanomiadse — having nectocalyces ; hydrophyllia, with the 

 other organs, in a continuous series on the filiform coenosarc ; 

 tentacles with lateral branches ending in sacculi ; pneumato- 

 cyst small ; the sacculi may have no involucre, and a single 

 filament with biserial (Halistemma) or multiserial (Forskalia)^ 

 nectocalyces, and (especially in the former) a complex mus- 

 cular apparatus in the tentacles, or the lateral branches of the 

 tentacles may be involucrate with one (Stephanomia) or two 

 filaments, with a pouch-like middle lobe between ; in this 

 case, the coenosarc is sometimes highly contractile, with leaf- 

 like thin hydrophyllia, and polypitcs dispersed spirally on the 

 coenosarc. Stinging filaments surround the stem on all sides 

 (Agalmopsis) ; or the stem may be rigid, and not very con- 

 tractile, with thick wedge-like hydrophyllia one over another 

 (Agalma). In Crystallodes, the coenosarc is rigid, and the 

 polypites simply arranged on its ventral side, the tentacles 

 being between the hydrophyllia. 3. Physophoridae — necto- 

 calyces in a double row (2-5 pairs), each channeled in- 

 ternally to fit the coenosarc, and with four radial and a circular 

 uniting canal. There is no pneumatocystic stigma, nor hydro- 

 phyllium, but an apical pigment spot in the pneumatophore, 

 and a series of proximal hydrocysts, with or without filiform 

 tentacles, ex. Physophora, Stephanospira. 4. Athorybiadae — 

 nectocalyces, none ; the globular cavity of the coenosarc nearly 

 filled with the large pneumatocyst ; hydrophyllia on the 

 proximal side of the other appendages ; tentacular branches 

 with involucral sacculi ; two filaments, and a median fluid- 

 holding lobe, ex. Athorybia. 5. Rhizophysidse — coenosarc 

 filiform ; nectocalyces and hydrophyllia none ; pneumatocyst 

 small, in a pear-shaped pneumatophore, and with a red patch 

 at its stigma, through which the sac can expel the contained 

 air; the tentacles have lateral branches, but no sacculi nor 

 muscle-bands, ex. Rhizophysa. 6. Physaliadse — hydrosoma 

 pear-shaped, with no hydrophyllia nor nectocalyces ; ccenosarc 



