Phylum Hemichordata Subphylum Urochordata Subphylum Cephalochordata

PHYLUM CHORDATA

I. Subphylum Urochordata
A. Class Ascidiacea
B. Class Larvacea
C. Class Thaliacea
II. Subphylum Cephalochordata
III. Subphylum Vertebrata

SUBPHYLUM CEPHALOCHORDATA

occur worldwide in warm temperate and tropical seas
lives along ocean shores in coarse sandy or shelly bottom with the oral hood protruding
Limax lanceolatus (1774)
Amphioxus lanceolatus (1836)
Branchiostoma lanceolatus (1834)

Branchiostoma lanceolatus
Amphioxus

I. Integument: skin
II. Digestive
- oral hood: buccal cirri, vestibule, wheel organ, Hatscheck's pit, velum, velar tentacles
- mouth
- pharynx: peripharyngeal band, pharyngeal bars, pharyngeal slits, epibranchial groove,
hypobranchial groove (endostyle)
- digestive tube: esophagus, stomach, hepatic caecum, iliocolon ring, intestine, anus
- atriopore
III. Reproductive
- gonads
IV. Nervous
- notochord, neural tube or CNS
- eyes, brain vessicle, pigment spot, flagellated pit or olfactory funnel
V. Circulatory
- no heart, blood vessels, blood
VI. Excretory
- nephridia (solenocytes) VI. Others
- myotomes, myosepta
- fins: dorsal, caudal
- metapleural folds

Branchiostoma laceolatus (Amphioxus)

anterior section x.s.	middle section x.s.
middle section x.s. - female	posterior section x.s. - female

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