Analytical Synopsis of the Orde7' of Squall. 393 



Alopecoidae, 

 Cestraciontoidse. Odontaspidoidse. 



(Ginglymostomatoidse) 

 Galeorhinoidse. Lamnoidse. 



Rhinodontoidse. 

 The remaining groups can scarcely be said to form a regular 

 serial order. The following are regarded as peculiar or aber- 

 rant families. 



Heterodontoidse, 

 Notidanoidse. 

 The other families diverge in two regular series and in differ- 

 ent directions, but both tend towards the Rays : the Scylli- 

 orhinoids and their allies advancing towards the Rhinoidse, and 

 the Spinacoids and related families towards the Pristoid rays by 

 means of Pristiophorus. It may not be unnecessary to remind 

 some, that notwithstanding the relations thus alluded to, the 

 respective orders of Sharks and Rays are perfectly well defined. 

 The series referred to are the following. 



Spinacoidse. Ginglyinostomatoidse. 



Scymnoidse. Scylliorhinoidse. 



Echinorhinoidse. Crossorliinoidae. 



Pristiophoroidae. Rhinoidae. 



The affinity of the Crossorhinoidse to the Rhinoidse is mani- 

 fested by the depressed body and head, the terminal mouth, 

 and the posterior position of the dorsal fins of those fishes, as 

 well as by the fringed periphery of the head. The relations of 

 the family to the Scylliorhinoidae, and of the latter to the Gin- 

 glymostomatoidse, are sufficiently evident, and need only be 

 referred to. 



Most of the families of sharks are almost cosmopolitan in 

 their distribution, and representatives have been found wher- 

 ever the seas have been sufficiently explored. Some are, never- 

 theless, quite limited and represented by few members ; four 

 have no more than a single species each. 



The unique species of the Rhinodontoidge has only been found 

 at the Cape of Good Hope. 



