506 



PROCEEDINGS OF THE ACADEMY OF 



[Dec, 



Fig. 3. 



anterior end, which has sculpture of spiral cords only. The 

 intervals between ribs are crossed by low spiral cords 

 separated by narrower grooves, which extend part 

 way up the slopes of the ribs, but are wholly absent 

 near and at their summits. On the last whorl about 

 9 spirals may be counted in each intercostal interval. 

 The aperture is narrow, with a distinct but not deep 

 posterior sinus. 



Length 6, diam. 2.1 mm. 



From excavation of the lower locks at Gatun. 



Fasciolaria gorgasiana n. sp. PI. XXII, fig. 5. 



This species is represented by the last two whorls 

 minus the anterior canal. A fusiform shell with the 

 anterior extension quite narrow is indicated. The sur- 

 face slopes rather steeply from the suture to the subangular shoulder 

 and is ornamented on the last whorl with about 10 low, unequal 

 spiral cords. The shoulder bears conic tubercles, a little compressed 

 vertically, about 8 tubercles on each whorl. A cord at the shoulder 

 and two others below it override tubercles and intervals, but are 

 stronger on the tubercles. Below the shoulder the whorl is at first 

 convex and sculptured with strong alternating with weak cords, 

 then becomes concave, passing into the anterior canal. The col- 

 umella has a group of three strong plaits. The diameter of the last 

 whorl is about 21 mm. 



Gatun bed. 



This small species is related to the much larger F. intermedia 

 Sowb. of the Santo Domingo Oligocene, but on comparison with a 

 good series of that species it is seen that the coronal tubercles of 

 F. gorgasiana are more acutely conic and radiate more horizontally; 

 the last whorl also contracts more rapidly downwards. Fusus 

 quinquespinus Dall has much resemblance to this species, but there 

 arc only five spines on the last whorl. The type is fragmentary, 

 but so characteristic that there can be no difficulty in recognizing 

 it. Named in recognition of the services to the State of Col. Wil- 

 liam C. Gorgas. 



Nassa (Hima) praeambigua n. sp. PI. XXII, figs. 6, 7. 



The shell resembles N. ambigua Mont., being acutely ovate- 

 conic, the outlines of the spire straight, suture narrowly impressed, 

 iiorls not conspicuously convex except the last, which is rather 

 The apex is acute, first 2* whorls smooth, subsequent 



