Phylum : Hemichordata Notes, Examples & NEET MCQs (Class 11 Biology)

Definition

• Hemichordates are marine  invertebrate worm like animals.
• This is  phylum which has close  relationship with chordates and Echinodermata.

Hum isse pehle Phylum Echinodermata  ki   study kar chuke hai jinme excretory system absent hota hai.

• Hemichordata were considered as chordates but now put in a separate phylum under non chordata.

Sirf Notes hi nahi, is chapter ke Full Video Lectures aur MCQs ke liye hamara [NEET Biology Master Hub] visit karein — Jahan milega NEET 2026 ka complete study material ek hi jagah!

General characters 

• Hemichordates have a rudimentary structure in collar region called stomochord which is similar to notochord.
• Animals are worm like, marine with organ system level organisation.
• They are bilateral symmetrical, Triploblastic and Coelomate animals.
• Their Animals are cylindrical and body is divided into proboscis , Collar and trunk.

📌 Video Highlights & Quick Navigation:

• 00:07 - Hemichordata Introduction
• 00:48 - Examples: Balanoglossus & Saccoglossus
• 01:26 - Body Structure (Proboscis, Collar, Trunk)
• 02:58 - Stomochord vs Notochord
• 06:14 - General Characteristics (Marine, Coelomate)
• 07:49 - Excretion: Proboscis Gland (NEET Point)
• 08:06 - Reproduction & Tornaria Larva

• Circulatory system is open type.
• Respiration takes place by gills.
• Excretion take place by Proboscis glands.
• Saxes are separated. Fertilisation are external. Development is indirect.

🔥 NEET Flashcards: Hemichordata

• 📍 Habitat: Exclusively Marine (समुद्री जीव)
• 📍 Excretory Organ: Proboscis Gland (NEET MCQ ✅)
• 📍 Circulation: Open Type
• 📍 Larva: Tornaria Larva
• 📍 Notochord: Absent (Only Stomochord present)

Examples of Hemichordata

 Balanoglossus

• It is also  known as Acorn worm.
• It is deuterostome because anus is developed before mouth.
• It is worm like animals marine animals.
• Body is divided into proboscis, Collar and trunk.

Access Animal Kingdom Full Module ➔

• The alimentary canal is straight starting from mouth and ending with anus.
• It has U shaped paired gills slit.
• Notochord is present on upper part of body without nerve chord.
• Saxes are separated. Fertilisation are external. Development is indirect.

Saccoglossus

• It is soft body animals and body is divided into Proboscis collar trunk.
• It is found in spirally coiled burrow in ocean.
• It uses its proboscis to push the body on sand. 

Comparison table between Hemichordata and Chordata

Feature	Hemichordata	Chordata
Notochord	Absent (Stomochord present)	Present
Nervous System	Intra-epidermal	Central (Dorsal & Hollow)
Body Parts	Proboscis, Collar, Trunk	Head, Thorax, Abdomen

• Mouth is located internally at junction of Proboscis and collar.
• The gills are located internally in trunk region.
• It has  Glomerulus in proboscis which filter and release the excretory waste. 
• The egg are converted into tornaria larva which undergo metamorphosis into young animals.

Conclusion :

• Although Hemichordata is a small phylum, it is a goldmine for NEET aspirants. Understanding the structural nuances of the Stomochord and the functional role of the Proboscis gland is essential for scoring full marks in Animal Kingdom.
• ​We hope this guide and the accompanying video helped clarify your concepts. 
• Make sure to revise the comparison table regularly to avoid confusion between Hemichordates and Chordates.
•  If you have any questions, feel free to drop a comment below. Keep hustling, and good luck with your NEET journey!

Next post main hum  Chordates and vertebrates ki baat karenge jo non chordates se kuchh characters main bilkul different hote hai.

🎯 NEET MULTIPLE CHOICE QUESTIONS

🔥 100% CHALLENGE

"Questions yahi se aayega... taiyari jeet ki!"

1. Which of the following phylum were earlier considered as chordates but now is a non chordates under separate phylum.
A. Echinodermata
B. Hemichordata
C. Mollusca
D. Urochordata

Answer: B  

2. Which of the following structure is present in Hemichordates as rudimentary.

A. Spinal cord
B. Nerve cord
C. Notochord
D. Stomochord 

Answer: D 

3. Stomochord is present in Hemichordates in 

A. Proboscis region

B. Collar region

C.Trunk region

D. Glomerulus 

Answer: B 

4.Which one of the following statement is not correct with respect to Hemichordates.

A. They are worm like and present in both fresh and marine water.

B. They are Triploblastic and have bilateral symmetry.

C. They are true Coelomate with organ system of body organisation.

D. They have stomochord which seem like notochord.

Answer: A 

5.Body of Hemichordates is divided into 

A. Proboscis collar and trunk

B. Head and trunk

C. Thorax and abdomen 

D. Head, foot and visceral hump

Answer: A 

6. Hemichordates respires by

A. Trachea     B. Gills

C. Spiracle     D.lungs

Answer: B 

7. Proboscis glands in Hemichordates is involved   in 

A. Respiration 

B. Excretion 

C.Transportation

D. Locomotion 

Answer: B 

8. Consider the following features of Hemichordata and select the correct code

1. Open circulatory system 

2. External fertilisation

3. Separated sex

4. Indirect development 

A. 1 2 and 3

B. 2 3 and 4

C. 1 3 and 4

D. 1 2 3 and 4

Answer: D 

9. Which of the following animals belong  to Hemichordata.

A. Ctenoplana & Pleurobranchia 

B. Balanoglossus & Pleurobra chia 

C. Saccoglossus & Pleurobranchia

D. Balanoglossus and Saccoglossus

Answer: D 

10. Identify the number 1 and 2 in given Diagram 

A. Proboscis and Collar

B. Collar and trunk 

C. Proboscis and trunk

D. Collar and trunk

Answer: A

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