1758 Bulletin 4.7, United States National Museum. 



FAMILIES OF Lome ATI: 

 a. Myodome* more or less developed. 



&. Post-temporal bifurcate and connected with the cranium by its processes in 



normal manner. 

 c. Body and head compressed or moderately depressed.! 



d. Actinosts moderate and inserted on posterior edges of hypercoracoid 



and hypocoracoid ; ribs, typically, borne on enlarged parapophyses. 



e. Gills 3| or 4, the slit behind the last gill small or wanting ; spinous 



dorsal well developed ; anal with 3 strong spines, the fin rather 



short; body covered with scales; a single lateral line; top of 



head more or less armed; vertebra? rather few, 24 to 31. 



SCORPJENID.E, CLXXVI. 



ee. Gills 4, with a large slit behind the fourth ; body covered with 

 small scales ; cranium unarmed ; dorsal and anal fins elongate ; 

 vertebras numerous, more than 30. 

 /. Nostrils normal, the posterior Avell developed. 



ANOPLOPOMATID^E, CLXXVII. 



ff. Nostrils single, the posterior represented by a small pore 

 well behind the other and not functional. 



HEXAGRAMMID^:, CLXXVIII. 



dd. Actinosts large and partly intervening between the hypercoracoid 

 and the hypocoracoid ; ribs sessile on the vertebrae ; vertebras 

 numerous, 30 to 50 ; no anal spines ; body not uniformly scaled. 



COTTIDvE, CLXXIX. 



&&. Post-temporal expanded and connected with the cranium by an extensive 



suture. 



g. Anus submedian ; ventrals subabdominal ; gill openings very small ; exo- 

 skeleton developed as spiniform prickles ; head excessively large. 



RHAMPHOCOTTID^E, CLXXX. 



gg. Anus thoracic; ventrals subbrachial; gill opening moderate; exoskele- 



ton developed as plates arranged in about 8 longitudinal rows ; spi- 



nous dorsal short or wanting. AGONID^E, CLXXXI. 



DISCOBOLI : 



aa. Myodome completely wanting ; ventrals completely united, forming a round suck- 



ing disk, which is rarely obsolete; spinous dorsal little developed. 

 h. Body cavity elongate ; caudal region short. CYCLOPTERIDJE, CLXXXII. 



hh. Body cavity short; caudal region elongate; skin smooth. 



LlPARIDID^E, CLXXXIII. 



Family CLXXVI. S 



(THE ROCK-FISHES.) 



Body oblong, more or less compressed, the head large, and with one or 

 more pairs of ridges above, which usually terminate in spines. Opercle 



*Myodome or muscular tube, "a chamber for the rectus muscles of the eye. This is 

 isolated from the brain cavity by the development of a platform from the basioccipital 

 continuous with horizontal ridges or shelves diverging from the inner walls of the pro- 

 otic bones and meeting along the middle, thus constituting a roof for the muscular cham- 

 ber and a floor for the cranial cavity." (Gill.) 



tBody and head much depressed in the family of Platycephalidce and its relatives, 

 groups not represented in the Western Hemisphere. Two species of Platycephalus have 

 been erroneously ascribed to the region under consideration. These are mentioned on 

 page 2028. 



JThe original draft of the account of this family is contributed by Mr. Frank Cramer; 

 to this numerous additions have been made by the present authors. Some of the descrip- 

 tions are adapted from those in Jordan & Gilbert's Synopsis Fishes N. A. All these 

 nave been verified on new material. 



