HUBBS and VVISNER REVISION OF THE SAURIES 



main tube is about 0.1 mm. The tube is relatively 

 more fragile than it is in the larger forms, and 

 there is only a hint of the stain-resisting band of 

 tissue. 



Phar\ngeal Bones and Teeth 



The first pair of upper pharyngeal arches 

 I bones) is absent in all the scomberesocid fishes. 

 Also, the second pair of upper bones are so closely 

 appressed as to appear as a single unit and are not 

 notably larger than the third pair, which are not 

 closely appressed; the lower pharyngeal bones are 

 fused into one, as in the Synentognathi. Absence of 

 the first upper pair of pharyngeals in synentog- 

 nathous fishes has been reported by Collette 

 ( 1966) who figured the pharyngeal bones and teeth 

 of six species of the Belonidae: Belonion dibran- 

 chodon, B. apodion, Potomarraphis guianerisis, 

 Strongylura notata,Pseudo.stylusangiisticeps, and 

 Xenentodon cancila. Of these six. only B. apodion 

 and -Y. cancila lack the first (lower) pair of upper 

 pharyngeals: they also lack the second pair, re- 

 taining only the third (uppermost) pair. As figured 

 by Collette, but not discussed, the pharyngeal 

 teeth of these belonid species appear to have only a 

 conical type of tooth, with no cuspate or lobate 

 features. In apparent contrast, many of the 

 pharyngeal teeth of the scomberesocid species 

 treated below have more or less well-developed 

 lateral lobes or cusps, or are distinctly tricuspid. 



Cololabis isaira, 281 mm SL, 225 mm BL, from 

 the Gulf of Alaska (SIO 57-198). The greatest 

 length of the lower pharyngeal arch is 12.8 mm. 

 the greatest width 8.6 mm. The teeth are moder- 

 ately strong and curved. The marginal ones are all 

 slender and unicuspid but those within the margin 

 in the wider part are definitely widened, slightly 

 to greatly, medially, with usually on each side a 

 marginal lobe grading from rudimentary to. 

 rarely, a rather definite cusp. There is oftly a trace 

 of alignment (the arrangement is more nearly 

 quite indefinite). Along the interior, greatly nar- 

 rowed half of the length, the teeth, reduced in size, 

 are very roughly in three or four rows. The lateral 

 teeth do not form a definite row and are not mark- 

 edly enlarged. Toward the posterior margin the 

 teeth are large and irregularly crowded. Most of 

 the larger teeth bear a more or less well-developed 

 median, lengthwise, rather rounded ridge. 



Each bone of the second pair of upper pharynge- 

 als is 11.8 mm long and 3.0 mm wide. Anteriorly 



and marginally the teeth are slender, moderately 

 curved, and almost strictly unicuspid. Over the 

 major portion of each bone, however, the teeth are, 

 for the most part, definitely tricuspid, with the 

 lateral cusps submedian and occasionally rep- 

 resented by weak to strong lobes. Between the left 

 and right arches there is, posteriorly, a triangle of 

 dermal ridges, medially a low ridge, and an- 

 teriorly a high ridge reaching to the surface with a 

 strong fimbriation. As in the lower pharyngeal, 

 the teeth are crowded and irregularly show just a 

 trace of oblique seriation. 



Each bone of the third pair measures about 2.3 

 ^ 6.7 mm. The teeth are nearly concealed in the 

 strong fimbriation of the surface, and all are small, 

 irregularly arranged, moderately curved, and un- 

 icuspid. 



Elassichthys adocetus, 58.0 mm SL, 49 mm BL, 

 from off Peru at 08°07 ' S, 84°58 "W (SIO H 52-380). 

 The lower pharyngeals are about 2.6 mm long and 

 1.1 mm wide. The teeth are relatively few, not 

 more than about 10 across at the widest part of the 

 arch. Most of the relatively large teeth in the me- 

 dian portion of the broad posterior region are 

 broadened and to a varying degree tricuspid, with 

 the central cusp much stronger than the lateral 

 ones. The teeth along the posterior edge are rather 

 broadly lanceolate rather than very slender as in 

 Cololabis. Anteriorly, where the arch narrows, the 

 teeth become weak. In the rows along the outer 

 margins the teeth are relatively conical and mod- 

 erately curved. The teeth across the posterior field 

 are much larger than others and bear a median 

 lengthwise ridge. Near the middle of the arch are 

 only about four teeth in cross section. 



Each bone of the second pair measures approxi- 

 mately 0.6 X 1.5 mm. The teeth are relatively 

 robust and uniformly the sharp, definitely unicus- 

 pid tip is bent sharply. On the broad part of the 

 bone there are only about five teeth in cross sec- 

 tion. A membranous septum, very weakly pat- 

 terned, extends the whole length between the two 

 bones. 



Each of the third pair of bones measures about 

 0.4  0.9 mm. The relatively few teeth are all 

 unicuspid with the tips bent backward. 



Sconi beresox saurus scombroides . 290 mm SL, 

 205 mm BL. from off Chile. 34' 30 ' S, 79"30 ' W ( SIO 

 58-263). The lower pharyngeal has a midline 

 length of 11.4 mm. a maximum width of toothed 

 area (at posterior edge) of 7.3 mm. and a width 



549 



