tu pro occipital 



ipiwnoric 



Figure 29.—Macrorhamphosodes uradoi: 

 lateral view of head; 69.9 mm SL, Japan. 



branchiottagal rays 

 intaropwculum 

 •pihyal 





snout, the last three dorsal spines rudimentary and the 

 second pelvic fin ray absent, all of which features are 

 foreshadowed in Bathyphylax, in which the snout is of 

 moderate width, the mouth slightly to distinctly supra- 

 terminal, the lips thin, the teeth conical and slightly 

 reduced in number in both jaws, the last two or three dor- 

 sal spines rudimentary, and the second pelvic fin ray ab- 

 sent. 



Subfamilial relationships, and relationships to the 

 Triacanthidae and Gymnodontes.— Since the shape of 

 the posterodorsal region of the skull and of the portion of 

 the pelvis posterior to the pelvic spines, the primary dis- 

 tinguishing features of the two Recent subfamilies, is not 

 known in the two fossil subfamilies, a pertinent question 

 about the basal genus in each of the two Recent sub- 

 families is which comes closest in basic structure to the 

 ancestral stock which gave rise to them: was it a stock 



with a domelike supraoccipital separating the epiotics on 

 the dorsal surface of the skull and with a shaftlike pelvis, 

 or a stock with a flattened supraoccipital bearing a 

 medial crest and allowing the epiotics to meet on the dor- 

 sal surface of the skull and with a basinlike pelvis, or 

 perhaps a stock with intermediate conditions? In the 

 absence of a solution from the fossil triacanthodids there 

 is but one clue as to which condition is more likely to 

 have been that of the early triacanthodids, and that is 

 the condition of the supraoccipital and epiotics in the 

 acanthurids, which are often considered to have evolved 

 in the Eocene from the same Cretaceous stock (perhaps 

 the Pharmacichthyidae, according to Patterson 1964) as 

 that which gave rise in the Eocene to the triacanthodids 

 and other plectognaths. 



The supraoccipital of acanthurids is basically dome- 

 like and without a flattened basal portion, while the 

 epiotics are separated from each other medially on the 



Figure 30.— Halimochirurgiu centrUcoidee: 

 lateral view of head; 99.2 mm SL, Bay of Bengal. 



