the frontals, in contrast to Colomesus (family 

 Colomesidae), another genus with two nostrils, in which 

 the sphenotics are large and prolonged anteriorly to meet 

 the prefrontals, excluding the frontals from the orbital 

 margin. 



I agree that the generalized condition of the nasal sac 

 with two nostrils probably does link the "Lagoceph- 

 alidae" and "Colomesidae" in a natural group as ap- 

 posed to the "Tetraodontidae," and that Sphoeroides is 

 distinctive among them in retaining the generalized con- 

 dition of the lateral line. However, when numerous 

 species are examined the osteological differences 

 between the groups are not as clear cut as previously 

 thought, and they scarcely merit familial recognition. 



For example, Colomesus does have the sphenotics 

 prolonged anteriorly further than in any other tetra- 

 odontid, and the posterior recurving of its anterolateral 

 region is also distinctive. However, the sphenotics 

 become fully prolonged anteriorly to meet or very nearly 

 meet the prefrontals and exclude the frontals from the 

 margin of the orbit only in specimens of about 100 mm 

 and larger (see Tyler 1964 for illustrations of the skull at 

 various sizes). At sizes of about 50 mm the skulls of the 

 two species of Colomesus bear a strong resemblance to 

 those of Sphoeroides annulatus and formosa, both of 

 which, like Colomesus, have the frontal narrower poste- 



Figure 265.— Dorsal views of skulls of: left, 

 Amblyrhynchotes honckenii, 97.4 mm SL, Mozambique; 

 right, A. richei, 59.4 mm SL, New Zealand. 



riorly than anteriorly and the sphenotics prolonged ante- 

 riorly, although not as far forward in adults of S. an- 

 nulatus and formosa as in adults of Colomesus. In both 

 S. annulatus and formosa the anterior region of the 

 sphenotics is laterally expanded, although the expansion 

 is not recurved as in Colomesus. Among Sphoeroides 

 (including Guentheridia) only annulatus and formosa 

 have a dorsal flange of the parasphenoid meeting the 

 frontals in the interorbital septum, and one (psittacus, 

 along the coast of northern South America) of the two 

 species of Colomesus also has a dorsal flange of the para- 

 sphenoid while the other (asellus, fresh water of northern 

 South America) does not. 



Both species of Colomesus have two hypohyals, as does 

 S. annulatus, while formosa has only one. In Colomesus 

 there are numerous trituration teeth in both jaws, some- 

 times consolidated into paired plates, and both S. an- 

 nulatus and formosa have the same arrangement, 

 somewhat unusual among Sphoeroides. Colomesus has 

 minute teeth on the first pharyngobranchial and lacks an 

 interhyal, as do S. annulatus and formosa, along with 



