APPENDIX 541 



Sub-Order 10. Lophobranchii (sea-horse; pipe- 

 fish). 



Sub-Order u. Hemibranchii . (stickleback). 



Sub-Order 12. Acanthopteri (mackerel; cod; 

 perch; sculpin; flounder). 



Sub-Order 13. Pediculati (angler-fish; frog-fish). 



[In the Class of Pisces the process of extinction has left 

 in our modern fauna five more or less isolated groups, 

 usually treated as Orders. These are the Selachii, Holo- 

 cephali, Dipnoi, Ganoidei and Teleostei. The first is the 

 only remaining group of the elasmobranchs } of the second 

 and third the only fossils known are much like those of 

 the present day and their affinities have thus not been 

 definitely traced ; and the fourth and fifth are respectively 

 the earlier and later types of teleostomes. 



The living ganoids are very few in number and are 

 for the most part unrelated to one another. There are 

 but two crossoptergyians, and but one or two living 

 genera of each of the three groups Chondrostei, Protospon- 

 dyli, and ^Etheospondyli. At this point the " ganoids " 

 are considered to end, and the remaining Sub-orders, be- 

 ginning with the Isospondyli, are included with the tele- 

 osts (i. e. Teleostei, to be carefully distinguished from 

 Teleostomi, the larger group). 



Sub-orders 4-8 are sometimes grouped as the Physostomi 

 and the remaining sub-orders, 5-13, as the Physoclysti. 

 In the former of these the air-bladder retains its connec- 

 tion with the alimentary canal ; in the latter this becomes 

 lost during development and the air-bladder is a closed 

 sac.] 



Class II. Amphibia (Batrachia). 

 Order i. Urodela. 



Sub-Order i. Perennibranchiata (Necturus; Si- 

 ren). 



Sub-Order 2. Derotremata (Cryptobranchus). 

 Sub-Order 3. Salamandrida (newts ; salaman- 

 ders). 



Order 2. Gymnophiona (subterranean forms, with- 

 out limbs or eyes). 

 Order 3. Anura. 



Sub-Order i. Aglossa * (Surinam toad). 

 Sub-Order 2. Arcifera (toads; tree-toads). 

 Sub-Order 3. Firmisternia (frogs). 



