1738 Bulletin 4.7, United States National Museum, 



Tetrodon trichocephalus, COPE, Proc. Ac. Nat. Sci. Phila. 1870, 120, Gulf Stream off New- 



port, Rhode Island ; JORDAN & GILBERT, Synopsis, 862, 1883. 

 Sphceroides trichocephalus, JORDAN & EDWARDS, I. c., 236. 



2155. SPHEROIDES PACHYGASTER (Miiller & Troschel). 



Dorsal rays 10; interorbital width twice diameter of eye, or equal to 

 length of snout ; nostrils nearer eye than to tip of snout, papillary, with 

 2 openings. Dorsal fin in front of anal ; caudal truncate, upper and lower 

 points somewhat elongated. Body smooth all over in adult (probably 

 prickly when young). Color bright brown with darker spots on the back. 

 (Gttnther.) Length 14 inches. " A very scarce species around the Barba- 

 dos." (Giinther.) Not seen by recent collectors ; possibly the type of a 

 distinct subgenus. (rtaxvg, thick; yatfrrfp, belly.) 



Tetrodon ( Cheilichthys) pachygaster, MULLER & TROSCHEL iii Sckomburgk, Hist. Barbados, 



677, 1840, Barbados. 



Tetrodon pachygaster, GI)NTHER, Cat., vm, 287, 1870. 

 Sphceroides pachygaster, JORDAN & EDWARDS, I c., 235. 



679. OVOIDES, Laoepede. 



Let Ovoides, LACEPEDE, Hist. Nat. Poiss., 1, 256, 1797 (fasce; French names only) ; based 

 on front view of Tetraodon stellatus. 



Ovum, BLOCH & SCHNEIDER, Syst.Ichth., 530, 1801 (commersoni) ; after LACEPEDE; name 

 preoccupied in mollusks. 



Ovoidcs, DUMERIL, Zoologie Analytique, 1806; after LACEPEDE. 



Oonidus, KAFINESQUE, Analyse de la Nature 1815, 90 (substitute for Ovum). 



Arothron, MULLER, Abli. Berl. Akad. 1839, 252 (testudinarius=reticularis). 



Les Dilobomycteres (Dilobomycter), BIBRON, Revue Zool. 1855, 279 (reticularis, etc.). 



? Let Dichotomycteres (Dichotomy cter), BlBEON, Kev. Zool. 1855, 279 (flumatilis; no diag- 

 nosis). 



Body rather robust, the skin usually more or less prickly. Nostril on 

 each side with a tentacle, bifid to the base, its tips without opening, the 

 branches of the large olfactory nerve ending in cup-like depressions along 

 the inner edges of the two flattish lobes. Dorsal and anal fins short, 

 rounded, each of 7 or 8 rays; caudal rounded. Vertebrae usually 8 and 

 10. A ring muscle about the eye forming eyelids. Postirontals and pre- 

 frontals deflected, to describe the segment of the circle. Species numer- 

 ous, chiefly of the tropical Pacific ; distinguished from Spheroides by the 

 solid nasal tentacles, and from the still more closely related African genus 

 Tetraodon (Tetraodon lineatus, .) by the form of its frontals, the two 

 genera being similar in external characters, (ovum, egg; sido$, resem- 

 blance.) 



a. Interorbital space concave, its width nearly twice eye ; spines on body coarse ; color 

 dark, the back with round pale spots ; several parallel longitudinal streaks 

 below pectorals. ERETHIZON, 2156. 



aa. Interorbital space flattish, its width 1J times eye; spines slender; color yellow, 

 blue, or brown; back and belly with or without round pale spots; no distinct 

 dark streaks below' pectorals. SETOSUS, 2157. 



