The below mentioned article provides biology notes on Phylum Hemichordata. (Gk. hemi- half, chordate- notochord) Due to some similarities with chordates, some workers considered Hemichordata as a subphylum under phylum chordata. But, on grounds of its general organization, recent scientists, like Vander Horst (1939), Dawyd off (1948), Marcus (1958) and Hyman (1959), have given it the status of a phylum [...]
In this article we will discuss about Balanoglossus:- 1. Derivation of Balanoglossus 2. Geographical Distribution of Balanoglossus 3. Habit and Habitat 4. External Structures 5. Body Wall 6. Supporting Structures 7. Locomotion 8. Coelom 9. Digestive and Respiratory Systems 10. Circulatory System 11. Excretory System 12. Nervous System 13. Reproductive System 14. Development 15. Affinities and Systematic Position. Contents: Derivation [...]
The upcoming discussion will update you about the difference between stomochord and notochord. Difference # Stomochord: 1. The stomochord arises as an out pocketing from the roof of the embryonic gut, anterior to the pharynx. 2. Endodermal derivative. 3. It has a narrow lumen, opening into the pharynx. 4. The wall of the lumen is composed of a single layer [...]