jaws of those species for which the most counts were 

 made are shown in Table 3 and Figures 165-166 (for Lac- 

 toria cornuta, L. fornasinii, and L. diaphana; Ostracion 

 tuberculatus and 0. lentiginosum; Acanthostracion 

 quadricomis and A. polygonius; Lactophrys trigonus; 

 and Rhinesomus triqueter and R. bicaudalis). There is 

 nothing out of the ordinary in the tooth counts recorded 

 for the fewer specimens of the other species of ostraciids 

 examined but not listed above. In the Eocene Eolactoria 

 the total number of teeth in the jaws is not known, but 

 they seem to be slightly wider basally and more decided- 

 ly constricted distally or cusped than in the Recent 

 species, somewhat reminiscent of the teeth of balistids 

 (Tyler 1973a). 



In all species of the Indo-Pacific genera (Lactoria, 

 Tetrosomus, Ostracion, and Rhynchostracion) the dor- 

 sal and anal fin rays are modally 9 and the pectoral fin 

 rays modally 10, excluding the uppermost rudimentary 

 pectoral ray. In all of the species of the Atlantic genera 

 {Acanthostracion, Rhinesomus, and Lactophrys) the 

 dorsal and anal fin rays are modally 10 and the pectoral 

 fin rays modally 12 in all but Acanthostracion quad- 



Figure 151. — Acanthostracion quadricornis: 

 dorsal (left) and ventral views of skull, composite 

 based on several specimens, 58.2-350 mm SL, 

 Gulf of Mexico and Caribbean. 



ricornis, which has only 11 (see Tyler 1965a, b). Corre- 

 lated with the differences in the number of dorsal and 

 anal fin rays are similar differences in the number of 

 basal pterygiophores. In the Indo-Pacific genera there are 

 modally eight dorsal and anal fin basal pterygiophores 

 and in the Atlantic genera nine. In both cases the an- 

 terior divergent anal fin basal pterygiophores number 

 five. When one more than the modal number of rays is 

 present, there is also often one additional basal pteryg- 

 iophore. 



In all ostraciids there are two nostrils on each side, 

 nearly always in the form of two short upright tubes. 

 However, in Rhinesomus bicaudalis the anterior tube is 

 extremely bulbous (see Bohlke and Chaplin 1968:678, fig. 

 212; and Fig. 159 here) at all specimen sizes, while in 

 Lactophrys trigonus it becomes bulbous, to about half 

 the extent of that in R. bicaudalis, in large specimens. 



