MADE BY^ DR. ANTONIO RAIMONDI IN PERU. 271 



teeth on each side. Dorsal saddle broad, almost without indentations, except a 

 tongue which divides it into two unequal parts, the larger being on the dorsal 

 side, the smaller is unsymmetrical, sloping down obliquely to the superior lateral 

 lobe, \vhich is broad, short, and unsymmetrical. At its termination it is divided 

 into two branches, of which the upper is narrow and obscurely tridentate ; the 

 lower is divided into one simple and one bifurcate prong, all of the same length ; 

 above the terminal branches the lobe bears a large tooth on the upper side, and a 

 small one on the lower. The lateral saddle is a repetition, on a smaller scale, of 

 the preceding. The inferior lateral lobe is not more than half the size of the 

 superior, and shows only the rudiments of the same details, in the shape of three 

 minute teeth on the end. The inferior lateral saddle, bending round the umbilical 

 margin, is straight above, divided like the others into two unequal parts, of which 

 the largest is on the upper side, but, instead of the tongue, the division is produced 

 by two little teeth ; the upper part is further subdivided by another tooth. The 

 first lobe inside of the umbilicus is a mere bidentate tongue, with a little tooth 

 on the upper side; the second lobe is still more rudimentary, and is partly hidden 

 by the suture ; the included saddle is irregularly divided into three parts by two 

 teeth. 



Measurements. Greatest diameter, 3.0 in.; diameter of the umbilicus, 0.8 in.; 

 depth of umbilicus from the inner angle of the mouth, 0.8 in. ; width of body 

 whorl, 1.4 in.; greatest width of mouth, 1.5 in.; width of mouth at the dorsal 

 side, 1.1 in.; depth of emargination of the ventral side of the mouth, 0.3 in. 



Locality. From the " Quebrada de Colpamayo, in the immediate neighborhood 

 of Chota, Dept. of Cajamarca. Height 2000 metres. Cretaceous'?" 



Remarks. From the type of the shell, I agree with Dr. Raimondi in believing 

 this to be a Cretaceous species. Its septum is remarkably simple, but, at the same 

 time, its simplicity has nothing that would suggest or approach to Ceratites. It is 

 rather that usually observed in a young Ammonite that has not yet developed its 

 details, although my specimen, as will be observed above, is 3 inches in diameter. 

 Prof. Hyatt's note, on returning me the specimen, is: "This is undoubtedly my 

 Buchiceras hilohatum from Cachiyacu, but is an older specimen than that described 

 by me." 



A. Ollonensis, n. s., Pi. 38, flg. 4, 4a. 



Shell discoidal, compressed, umbilicus small, shallow; sides converging with a 

 gentle curve ; dorsum narrow, slightly concave. Sides slightly undulated by very 

 broad rudimentary ribs ; a row of small tubercles on the umbilical margin, and 

 numerous small compressed tubercles bordering the dorsal margin, which are 



