281 



Sutural line not sufficiently well preserved to admit of an exact descrip- 

 tion of the whole or even of most of it. 



East end of Maud Island, one imperfect specimen about forty milli- 

 metres, or a little more than an inch and a half, in its maximum diameter; 

 and two miles south of Yakoun Lake, a similar but rather smaller speci- 

 men ; both collected by Dr. Newcombe in 1895. 



From its general resemblance to the Ammonites denarius of Sowerby, 

 as figured by D'Orbigny, this small Ammonite would seem to belong to 

 what Zittel calls the group of A. interruptus, Brug., and to be most 

 nearly related to Hoplites Vancouverensis (the Ammonites Vancouverensis 

 of Meek) and to Pachydiscus Gollevillensis, (D'Orbigny) as recentlv il- 

 lustrated by Kossmat. II. Vancouverensis, however, is a much larger 

 species, the shell of which, when adult, attains to a maximum diameter of 

 nearly five inches. Its periphery or venter, too, is more flattened, and 

 the tubercles which bound it on each side are elongated at almost a right 

 angle to the ribs from which they proceed, so that each pair of tubercles 

 is parallel, and not convergent forward, as those of //. Yakounensis are. 

 P. Gollevillensis, has a proportionately wider umbilicus than that of the 

 present species, and the tubercles on the outer margin of each side of the 

 outer volution of the former are more nearly transverse to it. 



Hoplites Newcombii. (N. Sp.) 

 Plate 37, figs. 1 and la. 



Shell small, modei'ately convex but somewhat compressed laterally, and 

 rather widely umbilicated. Volutions about five, the later ones lightly 

 embracing, so thxt about one-half of the sides of the inner ones are ex- 

 posed in the umbilicus. Outer volution a little broader than high, 

 rounded subhexagbnal in transverse section : umbilicus occupying about 

 one-third of the entire diameter, though its margin is rounded and 

 indistinctly defined. 



Surface marked by very numerous, close-set, thin and sharp transverse 

 ribs, most of which bifurcate from a minute flattened spinose tubercle, at 

 a short distance from the umbilicus, pass over the venter and reunite at a 

 corresponding tubercle on the opposite side. Between two of these 

 longer and continuous ribs, a short and simple rib is frequently interca- 

 lated. 



Sutural line unknown. 



Maximum diameter of the only specimen known to the writer, thirty-six 

 millimetres ; breadth of the outer volution at the aperture, sixteen mm. 

 and a half. 



South side of Alliford Bay, Dr. Newcombe, 1895 : a single well pre- 

 served specimen. 



