72 PALAEONTOLOGY OF CALIFORNIA. 



tionately smaller ribs, no nodes, and in details of the septum. It is not rare at 

 the locality mentioned above, but bus never been reported from elsewhere. It is 

 the smallest Cephalopod in the Cretaceous formation of California, so far as is yet 

 known. 



H. BREWERII, n. s. 



PI. 14, Fig. 22, and 22, a, b. 



SHELL small, whorls slightly compressed. Surface marked by 

 small oblique ribs, encircling the whorls, faintest on the ventral 

 side. At intervals of every four or five ribs there occurs a much 

 larger one, faint on the ventral surface, but prominent on the 

 sides and back. These ribs bear a small tubercle on each side of 

 the dorsum. 



Septum unequal on the upper and lower side. Dorsal lobe 

 larger than the others, rather slender, bifurcate ; each branch with 

 a lateral spur externally and two smaller ones above. Dorsal 

 saddles nearly equal, bilobate at the extremities. Superior lateral 

 lobes shorter than the dorsal. The one on the lower side is broad, 

 with the sides nearly parallel; the other is of the same shape as the 

 dorsal, except that the terminal branch on the dorsal side is longer 

 than the other. Lateral saddles of the same pattern as the dorsal, 

 the upper one being broadest. Inferior lateral lobes of the same 

 pattern as the dorsal, the lower one being largest. Ventral sad 

 dles very small, equal and simply notched. Ventral lobe not as 

 large as one of the branches of the dorsal; trifid at the extremity, 

 and with one small tooth above on each side. 



Length of the fragment, .85 inch. 



This species is founded on a single specimen, found by Prof. Brewer at Pence's 

 Eanch, twelve miles north of Oroville, Butte County, associated with Amnonites 

 Chicoensis, A. Rfmond'd, and many other species of Division A. 



