4 BULLETIN 214, UNITED STATES NATIONAL MUSEUM 



to a few species (whose identity must be doubted) and the paper 

 contributed little toward the solution of generic analysis. 



I have studied the pharyngeal bones of numerous species and have 

 found that the differences among groups of species are useful in 

 recognizing genera. The following species were so studied; some of 

 them are illustrated on plates 1 to 5: 



Scar ops: microps, perrico, rubroviolaceus, and j or dani. 



Chlorurus: gibbus, bicolor, and pulchellus. 



Scarus: aeruginosus, brevifilis, californiensis, coeruleus, compressus, croicensis, 

 dimidiaius, dubius, forsteri, globiceps, guacamaia, harid, lepidus, micro- 

 rhinos, niger, noyesi, oedema, perspicillatus, randalli, rhoduropterus, 

 scaber, schlegeli, singaporensis, sordidus, vetula, and madagascarensis. 



Scaridea: zonarcha. 



Sparisoma: abildgaardi, chrysopterum, lorito, and rubripinnis. 



Calotomus: spinidens, japonicus, and xenodon. 



Leptoscarus : vaigiensis. 



Cryptotomus : roseus. 



Nicholsina: beryllinus, denticulatus, and ustus. 



Euscarus: cretensis and strigatus. 



Other species whose pharyngeal apparatus was not removed are 

 referred to various genera on the basis of their close relationships with 

 other species on which disections were made. 



In order to determine the number of vertebrae/ radiographs were 

 made for ail recognized species in the family except Chlorurus nigri- 

 pinnis, Scarus cyanescens, S. africanus, S. rubrofasciatus , and S. 

 guttatus, for which no specimens were available. The radiographs of 

 708 specimens distributed among the genera and species, as recorded 

 in table 1, all showed a total of 25 vertebrae, without variability. 



After a study of prepared skeletons of parrotfishes it was possible 

 to distinguish the abdominal vertebrae from the caudal vertebrae in 

 the radiographs. The first vertebra with a fully developed haemal 

 spine, or one that reached past the tips of the first few anal ptery- 

 giophores, was considered as the first caudal vertebra. It was found 

 that the subfamily Sparisomatinae had 9 abdominal and 16 caudal 

 vertebrae, whereas the subfamily Scarinae had 10 to 12 abdominal 

 and 13 to 15 caudal vertebrae. 



For all species in the subfamily Sparisomatinae, the ninth abdominal 

 vertebra never had any trace of a haemal spine, whereas the next 

 vertebra (the tenth, or first caudal) always had a fully developed 

 haemal spine that reached past the tips of the first few anal ptery- 

 giophores. 



In the subfamily Scarinae the tenth or eleventh or twelfth may or 

 may not possess a rudimentary haemal spine, such a short spine 



1 The author is most grateful to the Research Corporation of New York for a grant that enabled him to 

 equip an x-ray apparatus in the division of fishes for study of osteology. 



