CLASSIFICATION OF VELELLA
PHYLUM :- COELENTRATA (Tissue grade, diploblastic and acoelomate. )
CLASS :- HYDROZOA (The hydroids and craspedote medusa )
ORDER :- CHONDROPHORAE (Float forms a disc like structure)
SUB-ORDER :- PHYSOPHORIDA (Upper end of colony contains float or pneumatophore, without swimming bells or bracts and with simplified cormidia. )
FAMILY :- CHONDROPHORAE (Float forms a disk like structure.)
GENUS :- Velella (Little sail)
Commonly found in warm sea; Pacific coast from Puget Sound to Mexico, South Atlantic coast; occasionally off New England.
HABIT AND HABITAT
Velella is polymorphic marine colonial form.
GENERAL CHARACTERSTICS OF VELELLA
- Velella is referred as sail by wind animal.
- It is most beautiful open-sea form.
- Deep blue colony consists of a rhomboidal disk pneumatophore or float containing air chambers without marginal identations.
- Float differs from Porpita having a clear transparent vertical ridge or crest passing obliquely across the float and called as sail. Both float and sail are filled with gases.
- On ventral surface hangs a single large gastrozooid and edge of disk is beset with numerous dactylozooids or tentaculozooids. Gonozooids are found around gastrozooid.
- Gonozooids produce free medusae.
- Velella is one of the most beautiful open-sea forms.
- The animal contains sail, short dactylozooid, gastrozooid, gonozooid and all above characters, hence it is Velella. Instructions: Compare Porpita and Velella.