16 BULLETIN 214, UNITED STATES NATIONAL MUSEUM 



dentigerous surface with 1 to 3 rows of molarlike teeth; lower pharyn- 

 geal bone single, bearing rows of molarlike teeth; vertebrae always 25. 

 Since my studies indicate that certain characters are important in 

 grouping paiTotfishes into phyletic lines, it seems advisable to recog- 

 nize certain of these groups of species as full genera and others as 

 subgenera. The following key distinguishes the genera and subgenera 

 recognized: 



KEY TO THE GENERA AND SUBGENERA OF SCARIDAE 



la. Cheek with 2 to 4 (4 in one Atlantic species) rows of scales below eye (fig. 5), 



second row may be represented by one scale ; teeth fully coalesced into a 



parrotlike beak, with median suture at symphysis of each jaw; edge of 



dental plate of lower jaw included in that of upper jaw when mouth is 



closed; pectoral rays normally ii,ll to ii,15; dentigerous surface of lower 



pharyngeals longer than broad; gill membranes broadly joined to isthmus 



without a free fold across isthmus. Subfamily Scarinae. 



2a. Each upper pharyngeal bone v.ith a single enlarged row of teeth (see pi. 



2), no rudimentary row along base of the enlarged row except on small 



specimens of Xenoscarops; gill rakers of first gill arch 6 to 21 -{- 21 to 38. 



(Indo-Pacific.) Scarops, new genus 



3a. Three rows of scales on cheek. (East, Central, and West Pacific.) 



Scarops, new subgenus 

 36. Two rows of scales on cheek. (East Pacific.) 



Xenoscarops, new subgenus 

 26. Each upper pharyngeal bone with two enlarged rows of teeth (see pi. 1), and 

 along the outer base of the outer enlarged row occurs a rudimentary 

 row; 3 rows of scales on cheek; gill rakers 4 to 9+11 to 15. (Indo- 

 Pacific.) Genus Chlorurus Swainson 



2c. Each upper pharyngeal bone with a single enlarged row of teeth (see pi. 3), 

 and along the outer base of this row occurs a rudimentary row; 2 to 4 

 rows of scales on the cheek; gill rakers 12 to 30 + 25 to 50. (Atlantic, 



Indo-Pacific.) Genus Scarus Forsk§,l 



4a. Median predorsal scales 3. (West Pacific.) 



Ypsiscarus, new subgenus 

 46. Median predorsal scales 4. (Central and West Pacific, Indian Ocean.) 



Subgenus Scarus Forsk§,l 

 4c. Median predorsal scales 5 to 8. (Atlantic, Pacific, Indian Ocean.) 



Subgenus Heniistoma Swainson 

 16. Cheek below eye with 3 or 4 scales in a single row; front edge of dental plate 

 of upper jaw included within that of lower jaw when mouth is closed, 

 or edges of the dental plates oppose each other; teeth more or less 

 coalesced into a parrotlike beak or some of the teeth making up edge of 

 dental plate with free or almost free or distinct edges, or there may be 

 present externally pointed incisorlike teeth more or less imbricated and 

 in rows; pectoral fin rays ii,ll; gill rakers coarse, 2 or 3+1 + 6 to 12, the 

 raker at angle of arch may be difficult to distinguish from those on 

 ventral part of arch; upper pharyngeal bones with 3 rows of teeth on 

 each side (see pis. 4 and 5) ; dentigerous surface of lower pharyngeals 

 broader than long. Subfamily Sparisomatinae. 



