46 



its base, and slender in all its parts, profoundly divided 

 above into three large unequal terminal branches, which 

 are variously subdivided and sinuate. Superior lateral lobe 

 slender, but spreading its ramifications over a surface twice 

 as great as that occupied by the dorsal saddle ; ornamented 

 at the extremity by three great unequal spreading branches, 

 which are variously subdivided into from four to six or seven 

 branchlets, with numerous pinnae and smaller digitations. 

 Lateral saddle a little more than half as large as the supe- 

 rior lateral lobe, contracted aud oblique below, having at 

 the extremity four unequal divisions, three of which are 

 trifid, and the other bifid, and all having many irregular 

 subordinate pinnules with sinuate margins. Inferior lateral 

 lobe less than half as large as the superior, and divided into 

 about seven principal alternating branches, of which the 

 three nearest the extremity are larger than the others, and 

 each again divided into two more or less sinuous parts. 



The succeeding lobes rapidly diminish in size towards the 

 umbilicus, the first, second and third, being palmately divid- 

 ed at the extremity into five, four, and three, short unequal 

 branches, while those nearest the umbilicus are slightly ob- 

 lique, and nearly simple, or only ornamented by a few small 

 digitations. 



The superior lateral and larger auxiliary lobes, as well as 

 the dorsal and principal lateral saddles, have each, in addi- 

 tion to the divisions mentioned at their extremities, two or 

 more alternating lateral branches on each side, which are 

 more or less ornamented with pinnae and smaller sinuosities. 



Indeed in the structure of its septa, this is one of the most 

 complicated multilocular shells I have ever seen ; the sur 

 face of the cast being so completely covered by the numer- 

 ous branches of the lobes as to render it exceedingly diffi- 

 cult to follow out their various ramifications. Yet it is 

 probable they are in the outer volutions of larger individu- 

 als even more complex than above stated, as this description 

 is made out from the inner whorls (measuring only 1*90 



