Newell.] 480 [Jan. 18 



slowly in breadth and width from the last septum up for about 

 10 mm., then decreases equally on all sides to the constricted aper- 

 tures, forming an oval dome. It was probably half as long as the 

 whole shell (restored) and its contents must have been greater than 

 all the rest of the shell combined. On the base are a series of 

 cren ulations somewhat indistinct. 



The dorsal opening of the living chamber consists of six lobes 

 arranged symmetrically, three on each side of a median-dorsi- 

 ventral-line, and radiating from a centre which coincides closely 

 with the vertical axis of the chamber. The dorsal pair of lobes is 

 the largest, the median lobes are shorter and the third pair of lobes, 

 those toward the ventral opening, is the smallest and nearest to- 

 gether. A narrow slit about 1 mm. in width and 12 mm. long con- 

 nects these lobes with the single ventral opening. On this slit 

 there is a slight thickening, looking like the beginning of a fourth 

 pair of lobes. 



The ventral opening is ovate and is surrounded on all sides, ex- 

 cepting where it joins the narrow slit, by a shallow sinus. The 

 general appearance of the whole dorsal opening is that of a triangle 

 pointing downward ; from its apex a median line runs forward and 

 terminates in an oval, the ventral opening. 



The septa are slightly concave with very broad low dorsal saddle 

 and narrow ventral saddle on the sharp angle. The smallest septa 

 are near together, about 1mm. apart, and above these the closed 

 chambers increase regularly in height to the third from the last, 

 then decrease slightly to the last chamber. 



The sutures show the crcnulations continuous with those of the 

 bottom of the living chamber so that a large part of the surface 

 shows faint vertical flutings, not represented in the illustration. 



The siphon is ventral, 1 mm. in diameter and slightly elliptical. 

 It is shown only on the smallest septum, at which place it is 3 mm. 

 from the ventral angle. In the figure of this septum, shown above, 

 the siphon is proportionally too large. 



The test and surface markings are not known. 



This species is represented b} T a single interior cast figured in full 

 size above. The dimensions of this casWire : — dorsi-ventral diam- 

 eter of living chamber 41mm., greatest lateral diameter 37mm., 

 height of living chamber along central axis, 23 mm. 



This species resembles H. callistoma and the discovery of other 

 specimens may prove this to be an American variety. It differs in 



