that the ethmoid-vomerine region is at least somewhat 

 shorter, while in richei the frontals over the rear of the or- 

 bit are very wide, at least as wide as more posteriorly, 

 and evenly taper anteriorly to bluntly rounded ends, in 

 front of which is an extremely short ethmoid-vomerine 

 region. The two species of Torquigener studied are about 

 as different in cranial configuration as A. richei is in com- 

 parison to A. honckenii and piosae. In T. pleurogramma 

 the frontal over the orbit evenly tapers to the posterior 

 edge of the prefrontal, and then more abruptly tapers 

 medial to the prefrontal, with a general configuration not 

 much different than that of, for example, Sphoeroides 

 testudineus, except for having a wider ethmoid. In T. 

 pleurostictus the frontal is laterally expanded over the 

 orbit, much wider there than more posteriorly, and only 

 begins to taper abruptly to a point at the posterior edge 

 of the prefrontal. The sphenotic in pleurostictus is more 

 anterodorsally expanded than in pleurogramma. The 

 major features of the skull in 10 species of Fugu has been 

 described and illustrated by Kuronuma (1943), who com- 

 pared their configuration to that of three species oiLago- 

 cephalus and one of Sphoeroides (pachygaster) . The 

 structure of three of the species of Fugu studied here 

 (rubripes, oblongus, and chrysops) more or less encom- 

 passes the diversity found by Kuronuma. In rubripes and 

 oblongus the sphenotic is somewhat anterolaterally ex- 

 panded; the frontal is laterally expanded over the orbit, 



Figure 268.— Dorsal views of skulls of: 

 left, Fugu oblongus, 46.2 mm SL, India; 

 right. F. rubripes, 151 mm SL, Japan. 



usually gently tapers to the posterior edge of the prefron- 

 tal, and then abruptly tapers medial to the prefrontal. 

 The skull of chrysops differs from the others by being ex- 

 ceptionally wide and having relatively straight lateral 

 margins, the frontal being especially wide. 



In all of the species oi Amblyrhynchotes, Torquigener, 

 and Fugu studied the parasphenoid has a dorsal flange in 

 the orbit meeting the frontals, there are small to minute 

 teeth on the first pharyngobranchial, a supraneural is 

 present but the interhyal is absent and there are essen- 

 tially no prootic medial prongs representing the remains 

 of the dorsal roof of the myodome. In all of the species of 

 these three genera studied there are one to three small 

 rounded trituration teeth in a single row to either side of 

 the midline of the upper jaw but none in the lower jaw, 

 except for A. richei, which had no trituration teeth in 

 either jaw. Amblyrhynchotes piosae has both dorsal and 

 ventral hypohyals, while the other two species (honckenii 

 and richei) of that genus have only the ventral hypohyal. 

 Torquigener pleurogramma has both hypohyals but 

 pleurostictus has only one. In Fugu all three species 

 studied {chrysops, oblongus, rubripes) had a single 

 hypohyal. Amblyrhynchotes richei is unique among the 



331 



