ENGONOCERATID &. 187 
The sutures have short broad saddles with narrow lobes, digitated 
only at the apical ends, and while the saddles remain about the same, the 
lobes imerease somewhat in the number of their digitations and in length 
with age. They are quite different on the right and left sides. The 
siphuncle is eccentric to the right, and ventral lobe follows this organ, but 
there is no very marked difference between the first lateral saddles in 
consequence of this. 
On the right side the first lateral has two branches so deeply divided 
by a bifid marginal lobe that it is really split into two distinct entire 
saddles, but these are more widely separated than in Meteng. acutwm, and 
are more nearly equal in size and aspect. Counting these as two saddles, 
there are thirteen saddles—ten narrow, entire, and phylliform, and three 
broad and bifid, the eleventh very deeply bifid, and the twelfth and 
thirteenth successively less deeply divided. The first and second lobes 
are bifid, the third to sixth bifid, but with four to eight digitations; the 
seventh to tenth simply bifid; the eleventh and twelfth, especially the 
eleventh, are divided by longer tongue-shaped saddles. 
On the left side the differences are as follows: The ninth to eleventh 
saddles are broad and bifid, the twelfth is broad and entire, the thirteenth 
is very broad and has a sinuous base, and inside of this a very minute lobe 
shows that there is a small fourteenth saddle. The eighth to the tenth 
lobes are simply bifid, the eleventh is unequally bifid, but has no long 
tongue-shaped marginal saddle; the twelfth is entire, and there is an 
excessively minute marginal thirteenth, as stated above. 
In the adult stage from the fifth saddles inward on both sides the sutures 
overlap slightly and the outlines are easily separable, but in the last five 
sutures this overlapping spreads to the third saddles and lobes and the out- 
lines are more compressed. This is accompanied by a shortening up of 
the saddles and lobes and a corresponding return of the younger proportions 
and aspect. 
In the metaneanic substage the primitive first lateral is divided into 
three low broad saddles by simple indented marginal lobes, and the magno- 
sellarian saddles are also divided, but the number of these was not ascer- 
tained. There were, however, only a few of these. 
Locality: Four miles east of Whitesboro, Tex. 
Age: Eagle Ford shales, Colorado group, Upper Cretaceous. 
