CANOIDEI. 



Tribe 2. Rajides (Skates and Ears). Plagiostomes, with li.-it 

 bodies ; with five gill slits opening on the ventral surface internal t.<> 

 the pectoral fins ; with complete pectoral girdle and cranial fin 

 cartilages, without anal fins. 



In consequence of the size and horizontal expansion of the thoracic 

 tins the fiat body presents the form of a large disc, prolonged behind 

 into the long thin tail, which is frequently armed with spines, rarely 

 with one or two serrated stings. The mandibles are short and stout, 

 and are furnished with teeth which may be either small and conical, 

 and arranged near one another in rows, or broad and plate-like. 

 The Rays live for the most part at the bottom of the sea, and feed 

 principally on Crustaceans and Molluscs. The Torpedos have an 

 electrical apparatus between the fin cartilages and the branchial 

 pouches. By means of this organ (fig. 590) they can stun even 

 larger fishes. Many Rays reach the considerable size of ten to 

 twelve feet. 



Fam. Squatinorajidae. Pristis a nti/j !/<>? m Lath. Sawfish, Ocean and 

 Mediterranean : TUiinobatits grawulatiis <'uv. 



Fam. Torpedidse. Electric Rays. Torpedo niarmuruta Uiso. Mediterranean 

 and Ocean : jYarr/t/r lirdxilii-tisis v. Ott. 



Fam. Rajidae. Skates and Rays. Raja clt/vaftt L. ; B. niimlrtiix L. 



Fam. Trygonidae. Sting Rays. Tri/r/oit j/n.^f/fiaca L. (Paxthmcn iinirimi 

 I'.cll). Atlantic Ocean. 



Fam. Myliobatidae. Eagle Rays or Sea Devils. Mi/liobati* nquillu L., 

 Mediterranean. 



Order 4. GANOIDEI.* 



Cartilaginous and bony Fishes, with enamelled scales, or with osseous 

 dermal plates and fulcra, with muscular conus arteriosus contain in ij 

 rows of valves; witJi comb-shaped gills and S'pii'fiJ ruin- In flie 

 intestine. 



In former periods of the world's history this order was richly and 

 variously represented (Sauroidce, Lepidoidai, Pt/cnodonta), while at 

 the present day it contains only a few forms (Lepidosteus, Polypterus, 

 Calamoicfithys, Amia, Acipenser, $caphirhynchus, Sj><itnlri<i). It is 

 dilficult to establish the limit towards the Tekosteans, since there is 



* Joli. Miiller, " Ueber den Ban und die Grenzen der Ganoiilcn." AJ>liun<Il. 

 (Irr Bt'i'liiu'r Ahdd., is Hi. 



J. Hyrtl, Uebcr den Zusammenhang der Geschlechts-und Harn\verkzeu^c 

 bei den Ganoiden. Drnlixclir. <lcr /.-. Alunl . der II Vxv, tixr/i.. '\' in. VIII.. Wien, 

 1854. 



Llitken, ' Ueber die Begrenzung und Eintbcilung der Ganoiden." Ueber- 

 setzt von Willemoes-Suhm. Paheontographica. 1S7J. 



