158 Proceedings of the Biological Society of Washington. 



end is distinctly larger than the basal, and the apicolateral radii are 

 curved, with the convexity upward. These scales are extraordinarily 

 similar in general type to those of some Ophidiidse, as Lepophidium 

 microlepis. 



SERRANID^. 



Petrometopon, Bodianus and Mycteroperca are Epinephelinse, and have 

 the characteristic elongated, parallel-sided scales of that subfamily. 

 Scales of P. panamensis are broader than those of the Australian 

 Epinephelus megachir, but otherwise little different. Paranthias furcifer 

 (subf. Anthiinse) has scales about 5 mm. long and 3.5 broad, entirely 

 of the Petrometopon type. Thus it appears that the Anthiiufe can not 

 be separated from the Epinephelinse on the scales. Bodianus acan- 

 thistius scales, only about 2.5 mm. long, are structurally like the 

 others, but with rather conspicuously bulging or convex sides. Myctero- 

 perca is like Bodianus, but the scales are larger and the sides straighter. 



H^MULID^. 



The scales in this family, so far as seen, are very uniform, subquadrate, 

 usually broader than long, always with the lower margin crenate or 

 scalloped, a character which distinguishes them from the Sciaenidse, 

 In Pomadasis the scales are about as long as broad, and the marginal 

 teeth are pointed. In Orthostoechus the scales are broader than long, 

 length about 3, breadtli 3.75 mm. ; the marginal teeth are pointed. In 

 Orthopristis the marginal teeth are subtruncate or obscurely bifid, and 

 the scale is very little broader than long. 



XYSTAEMATID^. 



The scale of Gerres rhombeus appears cycloid, but under the compound 

 microscope the ctenoid patch, of weak transversely diamond shaped 

 dentiform structures, can be seen. These are even crossed by broken 

 and rudimentary transverse circuli. In the Eucinostomus these ctenoid 

 elements are narrower and rather more distinctly dentiform, without 

 rudiments of circuli; but the general type of structure is the same. 

 The Australian Xystaema darnleyensis has lost the ctenoid patch alto- 

 gether. Both the Panama species have transverse circuli reaching the 

 middle of the lateral margin at right angles with it. 



SCIAENID^. 



The lateral circuli are directed vertically, instead of transversely as in 

 the last family. The scales are broader than long, and the lower margin 

 is without distinct crenulations. Leaving out Cynoscion, the scales are 

 of a very uniform type, but Paralonchurus dumerili is readily separated 

 from the others by the comparatively long and narrow elements of the 

 ctenoid patch. It has the marginal spines stout, obtusely pointed. 



CICHLID^. 



Cichlid scales are broader than long (sometimes not greatly so), with the 

 lateral circuli vertical, and the basal margin strongly crenate. In my 



