PEKCID^. 375 



greater portion of the lack ; spinous dorsal well developed, gener- 

 ally with stiff spines, of moderate extent, rather longer than, or 

 as long as, the soft ; the soft anal similar to the soft dorsal, of 

 moderate extent or rather short. Ventrals thoraeie, with one 

 spine and with four or five rays. 



First Family — Pekcid^. 



The scales extend hut rarely over the vertical fins, and the 

 lateral line is generally present, continuous from the head to the 

 catidal fin. All the teeth simple and eonieal ; no harhels. No 

 hony stay for the prceoperculum. 



A large family, represented by numerous genera and species 

 in fresh waters, and on all the coasts of the temperate and 

 tropical regions. Carnivorous. 



Fossil Percoids abound in some formations, for instance, 

 at Monte Bolca, where species of Labrax, Lates, Smerdis and 

 Cyclopoma (both extinct), Dules, Serranus, Apogon, Therapon, 

 and Pristipoma have been recognised. Paraperca is a genus 

 recently discovered in the Maries of Aix-en-Provence. A 

 species of Perca is known from the freshwater deposit of 

 Oeningen. 



Peeoa. — All the teeth are villiform, without canines ; teeth 

 oil the palatine bones and vomer ; tongue toothless. Two dorsal 

 fins, the first with thirteen or fourteen spines ; anal fin with two 

 spines. Prseoperculum and praeorbital serrated. Scales small ; 

 head naked above. Branchiostegals seven. Vertebrae more than 

 twenty-four. 



The "Freshwater Perch" (Perca fluviatilis) is too familiarly 

 known to require description. It is generally distributed 

 over Europe and Northern Asia; and equally common in 

 North America, there being no sufficient ground for separat- 

 ing specifically the specimens of the "Western Hemisphere. 

 It frequents especially stiU waters, and sometimes descends 

 into brackish water. Its weight does not seem to exceed 



