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common name - dog fish

Habitat:open sea

Distribution: Zanzibar to Ceylon,Ceylon to Malay Archipelago in Indian Ocean from Bay of Bengal,East Indies and the Philippine Islands ,from Mexico to Panama in Eastern Pacific ,from Labrador to Brazil in Atlantic ,from Cuba in West Indies and Eastern Coast of South America


1. Body - long, laterally compressed ,spindle - shaped tapering at both ends.

2. Body Length - 30 to 60 cm

3. Body Colour - dark grey on dorsal and lateral surfaces and pale on ventral surface

4. Body Division - Head , Trunk and Tail

5. Dorso- ventrally compressed head with wedge - shaped snout in front

6. Largest part of the body is trunkextending from behind the gill - slits upto the cloacal aperture.

7. Tail lies behind the cloacal opening.

8. Eyes - large and circular , present at the side of the body

9. Mouth -wide crescentric opening , present on the ventral side of the head.

10. Gill - Clefts - 5 pairs , present on lateral sides

11. Median Fins comprises of :

         a. 2 dorsal fin
         b. 1 caudal fin
         c. 1 anal or ventral fin

12. First Dorsal Fin - triangular and present in front of the middle of the body

13. Second Dorsal Fin - triangular and small and present mid-way between the first dorsal and tail

14. Caudal Fin present along the ventral and dorsal surfaces of Tail and forms dorsal and ventral lobe.

15. Anal Finpresent in the mid-ventral line . Length - 5 cm in front of caudal fin opposite to the second dorsal fin

16. Lateral Fins comprises of :

             a) 2 pairs of Pectoral Fin
             b) 2 pairs of Pelvic Fin

17. Pectoral Fins are large than Pelvic Fins

18. Pelvic Fins has a copulatory organin males called Clasper connected with its inner edge

19. An enlongated opening between the two pelvic fins called Cloacal Aperture

20. Lateral Line- a faint line running on either side of the body extending from head to the tail.


common name - hammer-headed shark

Habitat: marine shark live in deep water

Distribution: Tropical and Sub- tropical seas

Importance : It is caught for oil but yield is low


1. Body - elongated

2. Body Length -4-5 cm

3. Hammer shape Head i.e. head is flattened in front and expanded sideways into 2 conspicuous lobes

4. Mouth- Crecentric and ventrally situated

5. Nostrils present ventrally at the base of the lateral lobes

6. Gills- slits - 5 pairs and laterally present

7. Spiracles absent

8. Viviparous

9. Asterospondylus Vertebrae

10. Presence of 2 Dorsal Fin .First is situated in front of the pelvic fin and second is opposite to the Anal fin

11. Ferocious and attack its prey with its Head


common name - string - ray or whip- tailed ray

Food: Carnivorous. food contain crustaceans, molluscs, and small fishes