Branchiostoma

Question 1

v shaped muscle fibres

Answer 1

Myomeres

Question 2

divisions between myomeres

Answer 2

myosepta

Question 3

reproductive organs, located posteroventrally

Answer 3

gonads

Question 4

external portion of feeding apparatus

Answer 4

oral hood

Question 5

slender tentacles that fringe opening of oral hood

Answer 5

oral cirri

Question 6

chamber into which water and suspended food particles first enter the amphioxus feeding apparatus

Answer 6

buccal cavity

Question 7

entrance into the buccal cavity, located anteroventrally

Answer 7

inhalant aperture

Question 8

smaller opening within velum

Answer 8

mouth

Question 9

demarcates oral cavity from pharynx

Answer 9

velum

Question 10

extends along dorsal surface of body

Answer 10

dorsal fin

Question 11

filled by a gel-like substance, supports dorsal fin

Answer 11

fin ray boxes

Question 12

lies along, approximately, the posterior quarter of the ventral surface

Answer 12

ventral fin

Question 13

extends anteriorly from the dorsal fin and wraps around the rostrum

Answer 13

rostral fin

Question 14

expansion of dorsal and ventral fin extensions into the postanal tail

Answer 14

caudal fin

Question 15

ventrolateral fins extending anteriorly from the ventral fin almost to the anterior end of the body

Answer 15

metapleural folds

Question 16

the exit of the atrium, lies just in front of the ventral fin

Answer 16

atriopore

Question 17

exit of the digestive tract, opens ventrally just posterior to the ventral fin

Answer 17

anus

Question 18

midventral groove extending longitudinally along the floor of the pharynx

Answer 18

endostyle

Question 19

middorsal groove, extends longitudinally dorsally along the pharynx

Answer 19

epibranchial groove

Question 20

extends from the tip of the rostrum into the tip of the tail, it has a striated appearance and lies just dorsal to the pharynx anteriorly and the digestive tract

Answer 20

notochord

Question 21

lies dorsal to the notochord and extends almost as far anteriorly and posteriorly, for most of its length it is about a third as thick as the notochord

Answer 21

dorsal hollow nerve cord

Question 22

dark, at the anterior end of the nerve cord

Answer 22

frontal eye

Question 23

photoreceptors that appear as dark granules along the ventral part of the nerve cord

Answer 23

Hesse ocelli

Question 24

a series longitudinal finger-like bands that are united posteriorly to form an organ

Answer 24

wheel organ

Question 25

fringe the margin of the mouth

Answer 25

velar tentacles

Question 26

second chamber water enters, after passing through pharyngeal slits

Answer 26

atrium

Question 27

initial part of the postpharyngeal gut

Answer 27

esophagus

Question 28

expanded region directly following esophagus

Answer 28

midgut

Question 29

evagination of the ventral floor of the midgut to form a diverticulum

Answer 29

hepatic cecum

Question 30

posterior to the diverticulum the midgut narrows gradually into its posterior portion, an easily recognizable dark band

Answer 30

iliocolon

Question 31

a fairly straight, narrow tube that leads to the anus

Answer 31

hindgut