72 CEPHALOPODA. 



TULiTES. Plate X. fig. 16. Shell conoid ; volutions cari- 

 nated ; lower side granulated. Fossil at Grignon. 



FAMILY IV. SPHERULACEA. 



Shell globular, spheroidal, or oval; with the volutions 

 mutually enveloping, or the cells contiguous, curved in the 

 segment of a circle, and collectively forming a single envelope 

 to the central cavity. 



Genns 20.— MEL ONI A Lamarck. 



Generic Character Shell subspherical, multilocular ; 



spire central; volutions contiguous, convolute, tuniciform ; 

 cells numerous, narrow ; septa imperforate. 



Melonites sphceroidea. — The Round Melonia. Plate 

 X. fig. 17. Entirely globular, and divided by depressed ribs. 

 Fossil. 



Genus 21.— GYROGON A.— ZamarcA. 



Generic Character. — Shell spheroidal, concave within, 

 composed of linear, curved, canaliculate pieces; the external 

 surface with carinated, parallel, partly transverse ribs ; be- 

 coming spirally curved and uniting at each of the centres or 

 poles ; aperture round, sometimes closed, situated at the in- 

 ferior pole of the shell. 



Gyrogonites medicaginula. — Somewhat spherical, with 

 transverse keels, spiral at the extremities. Fossil at Mont- 

 morency. 



Genus 22 MILIOLA.— ZamarcA. 



Generic Character Shell transverse, ovate-globular, or 



elongated, multilocular; having transverse cells surrounding 

 the axis, and alternately covering each other ; aperture 

 very small, orbicular or oblong, situated at the base of the 

 last volution. 



Miliola oyato.— The Oval Miliola. Plate X. fig. 18. 



