162 GEANULATED. 



GNATHODON. Gray, 1837. (Tvadoc, gnathos, jaw-ttone ; oIoq, 

 oBovToc, odontos, tooth.) Fam. Mactracea, Lam. — Descr. Ovate, 

 posteriorly angulated, equivalve, thick, ventricose, inequilateral, 

 covered with a greenish brown epidermis ; umbo distant, pro- 

 minent ; hinge having in one valve a sharp, angular, notched, 

 cardinal tooth, and two lateral teeth, the posterior of which is 

 elongated, and the anterior angulated, tortuous, shaped like 

 a jaw-bone ; in the other valve, two cardinal and two lateral 

 teeth, the anterior of which is wedge-shaped; ligament internal, 

 cuneiform, placed in a deep cardinal pit proceeding from the 

 umbones ; muscular impressions two ; palleal impression having 

 a slight sinus. — Obs. Only one species is known, G. cuneatus, 

 fig. 83, from New Orleans. It is known from all other shells 

 by the character of the hinge. PL iv. fig. 88. 

 GONIATITES. De Haan. A genus composed of species of 

 Ammonites, Auct. in which the last whorl covers the spire and 

 the sinuations of the septa are augulated. PL xxiii. fig. 480. G. 

 striatus. 

 GONIDOMUS. Swainson. A sub-genus of Geotrochus, Sw. 



Pupa pagodus, Auct. Sw. p. 332. PL xxv. fig. 519. 

 GONIOSTOMA. Swainson, 1840. A sub-genus of Eulimus, thus 

 described, " spire elongated, of few whorls ; aperture contracted 

 at each end ; lips margined ; the pillar curving inwards ; the 

 base slightly notched. G. erubescens, Sw. Zool. Journ. i. 

 pL 5, f. 2." Sw. p. 335. 

 GONIOSTOMATiE. Bl. A family belonging to the order 

 Asiphonibranchiata, BL containing the genera Solarium and 

 Trochus. 

 GONOSPIEA. Swainson, 1840. A sub-genus of Pupa, thus 

 described, " spire perfectly cylindrical, of equal thickness, the 

 tip obtuse, with the whorls large ; aperture oval ; lips thick- 

 ened ; piUar with or without a plait. G. polanga. Desk. 

 Lesson, Yoy. pi. 8, f. 8." Sw. p. 333. 

 GEANULATED. (Granum, a grain.) Covered with minute 

 grains, rough. The granulated lip of Oniscia, (fig. 409) vpill 

 serve as an example. 



