Question

short note on the following..
1)book lungs of arachnida.
2) pectines of scorpions. (marks-10)​

Answer 1

1. Book lungs of arachnida

2. Pectines of scorpions

Step-by-step explanation:

Book lungs of arachnida:

1. A book lung is a respiration organ.
2. It is found in certain air-breathing arachnid arthropods such as scorpions and some spiders.
3. A series of thin plates is present in each book lung.
4. Thin plates  are arranged in relation to each other like the pages of a book.  
5. Thin plates are richly supplied with blood.  
6. Hemolymph is filled in the unfolded pages or plates of the book.
7. The folds maximize extensive surface for the exchange of oxygen and carbon dioxide with the surrounding air.
8. There are four pairs in scorpions and up to two in spiders.
9. No motion of the plates is needed to facilitate this kind of respiration  in most of the species.    

Pectines of scorpions:

1. Pectines are unique structures in the animal kingdom
2. Pectines are two mid-ventral organs of all scorpions.  
3. Pectines are comb-shaped limbs.
4. Pectines are located ventrally behind the walking legs
5. Scorpions use pectines to gather chemical  information about the environment, food etc.