CLASSIFICATION OF STERNASPIS
PHYLUM :- ANNELIDA (Metamerically segmented, coelomate and laterally symmetrical. )
CLASS :- POLYCHAETA (Many setae, clitellum absent. )
ORDER :- SEDENTARIA (Tubicolous, sedentary and proboscis not-protrusible, without jaws or teeth.)
GENUS :- Sternaspis
It is found in U.S.A. (Florida).
HABIT AND HABITAT
Sternaspis is a marine, tubicolous polychaete
GENERAL CHARACTERSTICS OF STERNASPIS
- Body is short and made up of about 30 segments.
- Head is formed by prostomium and peristomium.
- Prostomium is elongated and without any appendages.
- Peristomium is knob like and contains mouth.
- First three segments have incomplete bristles, segments 8 to 15 have setae while segments 5th, 6th, 7th and 16th to 24th are devoid of setae.
- Just below 7th segment is a pair of genital papilla.
- In Sternaspis spinosa, the prostomium is elongated and bifurcated like the proboscis of the Echiurida.
- Intestine is coiled and the anus is terminal and surrounded by gills.
- Below 7th segment body is durable shaped and posteriorly a cuticular thickening is present ventrally called as ventral shield. Ventral shield contains number of setae around its edge.
The animal has bifurcated proboscis like prostomium and all above features hence it is Sternaspis.