2 J^evieio of the Chcrtodonlidm 



ANALYSIS OF GEXKI^A OF CH .-FTODOXTID.E. 



a. Preopercle uiinimed ; dorsal spines not graduated, some of the median 

 spines longer than tlie last spines ; scales comparatively large : 

 {yowng \\\i\\ ihe Tholic1ithysioYn\.). 

 b. Snout (nasals, palatines, etc.) with premaxillaries articular and den- 

 tary bones much produced, beak-like : cleft of moutli, with max- 

 illaries short ; lateral line ceasing under soft dorsal. 

 r. Dorsal spines 12 or 13 ; soft rays about 20 (19 to 23). 



Phognathodes, 1. 



bh. Snout little if at all produced ; dorsal spines usually 12 to 14 ; anal 

 spines 3. 



Ch.^todon, 2. 



aa. Preopercle armed with a very strong spine at its angle ; (young without 

 Tholichthys form ?). 

 (1. Dorsal spines 8 to 14 ; vertical limb of preopercle above spine armed 

 or unarmed. 



POMACANTHUS, 3. 



Oenus I. PROOXATHODES. 



Progxathodes Gill, Proc. Ac. Nat. Sci. Phila., 1862, 238 {j^elta) (name 

 only.). 

 Type Chelmo pelta Glinther, (= Ghelmo aculeatiis Poey.). 



This geiuis, contMiniiig two species, P. longirostris and P. 

 aculeaius, seems to be intermediate between Chelmon and Clice- 

 todon, having the pi-odnced snont of the former and a fin-formnla 

 more like tliat usnally seen in tlie lattei-. Its value as a genus 

 is donbtful, its species differing less from those of Chelmon than 

 extreme forms of Clicetodcm differ from each other. Its two spe- 

 cies are, moreover, veiy distinct, the one (longirostris) liaving 

 small scales and a very long beak, while the other (acideatus), 

 has the scales large, and the beak not very mnch longer than in 

 some species properly referred to Clicetodon. 



ANALYSIS OF SPECIES OF PROGNATHODES. 



a. [Snout moderately produced, about half length of head ; profile steep, 

 concave. Maxillary reaching to middle of snout. Angle of pre- 

 opercle rounded, minutely serrate. Dorsal spines long and very 

 strong ; 4tli spine 2 in depth ; membrane between spines deeply 

 notched. Soft anal higher than soft dorsal : their basal halves 



