pharyngobranchial, pachygaster being the only species of 

 Sphoeroides examined lacking at least minute teeth on 

 this pharyngobranchial. The characteristics of the skull 

 of pachygaster were first well described and illustrated 

 by Kuronuma (1943). The possible relationships of S. 

 pachygaster to Lagocephalus is discussed subsequently. 



In addition to the anatomical diversity of Sphoeroides 

 discussed above (number of vertebrae, skull shape, rare 

 presence of a dorsal flange of the parasphenoid, rare loss 

 of teeth on the first pharyngobranchial), a few other 

 items can be mentioned. A dorsal and ventral hypohyal 

 are present in most species, but only a single hypohyal is 

 present in S. greeleyi and trichocephalus (and 

 Guentheridia formosa). An interhyal is absent in most 

 species, but it is present in greeleyi, maculatus, and 

 pachygaster. All species have two or more (most 

 numerous in annulatus, in a disorganized plate) tritura- 

 tion teeth to either side of the midline in the upper jaw, 

 but most species do not have trituration teeth in the 

 lower jaw, these being present only in S. angusticeps, an- 

 nulatus, dorsalis, and greeleyi (and Guentheridia for- 

 mosa) as three or more units, often tending to form a 

 platelike structure (especially with increasing specimen 

 size?) to either side of the midline. Remnants of the dor- 

 sal roof of the myodome are present in a few species. In S. 

 dorsalis medial prongs of the prootics are well de- 

 veloped, almost as well as described and illustrated 

 here for Lagocephalus laevigatus, while smaller prongs 

 are present in S. angusticeps and greeleyi. In S. 

 maculatus most specimens have only a very weak indica- 

 tion of a medial projection from the prootics, but lome 

 have moderately developed prongs about as large ..s in 

 angusticeps and greeleyi. 



The amount of variation in the structure of the dorsal 

 surface of the skull that is correlated with specimen size 

 can be judged from the illustration of four specimens of 

 S. maculatus ranging from 12.4 to 201 mm. 



While the above gives an idea of the anatomical diver- 

 sity to be expected within a speciose genus and at least a 

 broad view of the species relationships with one another, 

 a far more detailed analysis based on numerous external 

 features of all of the Atlantic species is given by Shipp 

 (1974), including several newly described species not 

 studied here. 



All of the six species of Lagocephalus have been ex- 

 amined to provide an additional survey of the anatomical 

 diversity to be expected within a genus. The variation in 

 skull structure in Lagocephalus is only slightly less than 

 that found in the far more numerous species of Sphoe- 

 roides examined. 



Three of the six species of Lagocephalus have relative- 

 ly deep chunky bodies and drab coloration and seem to 

 be closely related on the basis of external features alone, 

 differing mainly in scale pattern on the dorsum; lunaris 

 having scales from the snout to the dorsal fin, spadiceus 

 from the rear of the snout to no more than half way back 

 the distance between the head and dorsal fin, and iner- 

 mis with spmes totally absent. These three species have 

 the olfactory epithelium folded over the entire inner sur- 

 face of the sac, usually with two of the folds on the rear 



wall much larger than the others and themselves bearing 

 additional smaller folds. Two other species are somewhat 

 more elongate and conspicuously patterned and seem 

 closely related, laevigatus with a pattern of crossbars on 

 the dorsum and lagocephalus, slightly more elongate 

 than laevigatus, with a dark dorsum, often with black 

 spotting, and gradually paler ventrum. Both of these 

 species lack spines on the back but have them well 

 developed on the abdomen, and both tend to have only 

 one of the folds on the rear wall of the nasal sac much 

 larger than the others and itself bearing smaller folds. 

 The most distinctive species of Lagocephalus is scler- 

 atus, with an elongate and depressed body and distinctly 

 depressed caudal peduncle, and a color pattern of a dark 

 dorsum with pale and dark spots and reticulations 



Figure 257 .Sphoeroidet maculatus: dorsal 



views of skulls to show changes in shape, amounts 



of cartilage viaible, and degree of auturing with 



increasing specimen sizes, as indicated, 



12.4-201 mm SL, New Jersey and Virginia. 



