68 CLASS XIV. 



Loxodon MuELL. and Henle. 



Galeus Cuv. (and Galeocerdo Muell. and Henle). Teeth acute, 

 with mai-gin crenate or serrate. 



b) Temporal foramina none. 



Carcharias Cuv. Eyes furnished with nictitating membrane. 

 Teeth acute, serrate. 



Sp. Squalus glaucus L., Bloch Ichth. Tab. 86, &c. 



Add sub-genera Tricenodon Muell. and Henle, Frinodon, Aprion, 

 Physodon Valenc, Scoliodon, on whicli see Muell. and Henle 1. 1. 



Bpliyra nob. Spliyrna Kafinesque, Bonap., Muell. and 

 Henle, Zygcena Cuv. Body elongate, with head transverse, broad, 

 and eyes lateral, supplied with nictitating membrane. Two un- 

 armed dorsal fins ; anal fin. Temporal foramina none. Teeth acute. 



Hammer-fish. In no other vertebrate animal does tbe head present so 

 strange a form as in this fish. It is prolonged in front of the mouth into 

 two transverse arms. It is only in the head of certain dipterous insects 

 {Addas, Diopsls), or in the position of the eyes upon long pedicles in many 

 decapod crustaceans, that we find a corresponding disposition. — The nasal 

 apertures are situated along the anterior margin of the broad head. The 

 name Sphyrna of Rafinesqde, which we think ought to be changed into 

 Sphyra {o-(pvpa, hammer), is preferable to Zygcena, already given to a genus 

 of Lepidoptera. 

 Sp. Sphyra malleus, Squalus Zygaina L., in the Mediterranean Sea; 

 and some other species in various other seas. Compare Valenciennes 

 sur le sous-genre Marteau, Mem. du Miis. ix. 1822, pp. 222 — 228, PI. 11, 

 12. With the exception of the singular head this genus is not very dis- 

 tinct from Galeus and Carcharias. 



Scyllmm Cuv. (species of Squalus L.). Body elongate, with 

 head short, obtuse. Anal fin. Two dorsal fins remote, the first 

 placed above the ventrals or behind them. Temporal foramina. 

 Eyes without nictitating membrane. Nostrils approximate to 

 mouth ; space between the nostrils and the quadrangular bone cir- 

 cumscribed by two parallel grooves running from the nostrils to tlie 

 mouth. 



Dog-fish. The teeth are provided with three points, of which the two 

 lateral are smaller. The dorsal fins are situated far backwards, as in 

 Scymnus. These species are oviparous. 



Sp. Scyllmm canicula, Squahis Canicula L., Bloch Ichth. Tab. 114, 

 Bonap. Faun. JtaL Tab. 131, fig. 1, &c. 



