328 



FISHES. 



Ceossorhinds. — The first dorsal behind the ventrals, the second 

 in advance of the anal, which is very close to the caudal. Tail 

 rather short. Eyes small. Spiracle a wide oblique slit, behind 

 and below the eye. Nasal and buccal cavities confluent. Head 

 broad, flat, with the snout very obtuse; mouth wide, nearly 

 anterior. A free nasal cirrhus ; sides of the head with skinny 

 appendages. Anterior teeth rather large, long and slender, 

 without lateral lobes, the lateral tricuspid, smaller, forming a few 

 series only. The fourth and fifth gill-openings close together. 



Three species are known from the Australian and Japanese 

 coasts. They are evidently ground-sharks, which lie concealed 

 on the bottom watching for their prey. In 

 accordance with this habit their colour closely 

 assimilates that of a rock or stone covered 

 with short vegetable and coralline growth — a 

 resemblance increased by the frond-like ten- 

 tacles on the side of the head. This peculi- 

 arity of the integuments, which is developed 

 in a yet higher degree in Pediculati and 

 Lophobranchs, is not met with in any other 

 Selachian. These Sharks grow to a length of 

 10 feet. 



Sixth Family^ — HYBODONTiDiE. 



Two dorsal -fins, each with a serrated spine. 

 Teeth rounded, longitadincdiy striated, with one 

 larger, and from two to four S7ncdkr lateral 

 eusps. Skin covered with sliagrccn. 



Extinct. From carboniferous, liassic, and 



triassic formations. Several genera have been 



distinguished ; and if Gladodus belongs to this 



family, it would have been represented even 



„ . in the Devonian. 



Fig. 118. — Spme 

 of Hybodus siih- 

 carinatus. SEVENTH FAMILY — CeSTRAGIONTID^. 



iVb nictitating menibrctnc. Two dorsal fins, the first 



