Jordan and EvcvDiann. — Fishes of North America. 1573 



Symphodus scina, 13 + 18=^31. 

 Crenilabiua inediteiraneiis, 13 



17 



Laclinolaimua maximus, 12 + 17 = 



29. 

 Diastodou scrota, 11 + 17 = 28. 

 Diastodon hirsutus, 11 + 17^28. 

 Anampses canuleopiinctatus, 11 + 



15 =-.26. 

 Duymseria aurigaria, 10 -f 15 = 25. 



Pseudolabrus celidotus, 10-f 13 = 



23. 

 Xyrichthys inacrolepidotus, 10 + 15 



= 25. 

 Xyriehtliys novacula, 9 + 16 = 25. 

 Cheilinua fasciatus, 10 + 13 = 23. 

 Dccodou puellaris, 12 + 16=28.* 

 Clepticiis parne, 10 + 17 = 27. 

 Cheiliiius trilobatus, 10 + 13 = 23. 

 Sparisouia creteuse, 11 + 14 = 25. 



As in most other large groups there has been shown considerable differ- 

 ence of opinion as to the characters which should be used in dividing the 

 Labroids into genera. The tendency with ;ill recent writers has been 

 toward a rather minute subdivision. The numbers of vertebra' seem to 

 us to yield characters of the highest importance. Other characters not to 

 be neglected can be drawn from the size of the scales, the numbers of the 

 dorsal spines, and the dentition. The degree of squamation of the head 

 seems to us to have an importance lower than that attributed to it by 

 Bleeker and Giinther, but it may be used for generic subdivision. 



«. Dorsal spines 8 or more, usually well distinguished from the soft rays ; anal spines 

 2 to 6. 

 Labrin^: 

 6. Vertebrae and dorsal spines in increased number, vertebra- about 36 (15 + 18 to 

 20 + 21) ; dorsal spines 14 to 21; anal spine.s 3 to 6, all the spines pungent; ante- 

 rior canines \; no posterior canines; lateral line complete; caudal fin never 

 forked; species of northern waters, rarely tropical, most of them European, 

 c. Anal spines 4 to 6; dorsal spines 16 to 21; cheeks and opercles scaly; scales 

 rather large ; preopercle serrate. 

 d. Teeth small, iu a single sei'ies; mouth small; dorsal fin nearly scaleless. 



Centrolabeus, 627. 

 cc. Anal spines 3. Teeth in more than one series. 



e. Preopercle serrate; opercles scaly; scales moderate; interopercle naked; 



snout not especially produced. Tautogolabrus, 628. 



ee. Preopercle entire ; opercles naked ; scales small ; interopercle naked ; 



snout blunt. Tautoga, 629. 



hh. VertebriB and dorsal spines not in greatly increased numbers; vertobrse 22 to 29 ; 



dorsal spines 8 tol3; anal spines 2 or 3; species of tropical or subtropical seas. 



/. VertebriS 27 to 29 (so far as known) ; dorsal spines usually 12 (11 to 14) ; sides 



of head more or less scaly ; preopercle serrulate or entire. 



* " It will be evident that iu those genera which are composed entirely or for the most 

 part of tropical species, the vertebral column is composed of 24, or nearly 24, vertebrie, 

 while those which are chiefly confined to the temperate seas of the Northern or Southern 

 Hemisphere have that number increased in the abdominal and caudal portions." (Giin- 

 ther, Cat., IV, 65). This increase in the number of vertebrie in the northern forms has 

 been used as a basis of the classification of the Pleuroneclidce, by Jordan and Goss, of the 

 Scorpeenidce, by Jordan and Gilbert, and it will doubtless prove to have a high value in 

 the subdivision of other families which have representatives in different zones. The 

 cause ot this peculiarity of fishes of cold waters is still obscure. Probably the reduction 

 innumber of segments is a result of the specialization of structure incident to the sharper 

 competition of the troi)ical waters, where the outside conditions of life are very favorable 

 for fishes, but the struggle of species against specie.s is most severe. (Jordan.) 



