KONGL. SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 181 



find that there is any foundation for this supposition. Trochonema differs from Oriostoma 

 through its elongate spire and from Cyclonema in the sculpture and the wide and open 

 umbilicus. 



1. TroclLonema turritum n. 



PI. XXI fig. 15—19. 



Shell elongated, turbinate, of seven whorls, angulated through the prominent 

 keels of which there are six on the body whorl, besides the sharply eminent one 

 around the umbilicus. The three lowest keels are sharper than those on the umbilical 

 side. The transverse lines of growth are thin, lamellar, with sharp edges, more or 

 less distantiated, the interstices varying in breadth from nearly two mill, to close con- 

 tiguity of the lainellaj. On the keels they are bent in a little tubular fold. The in- 

 terstices are finely and minutely striated by lines parallel with the enclosing lamellse. 

 On the umbilical ridge the transverse lamellte are crowded and the strias converge in 

 the interior of the umbilicus. The aperture is obovate, the longitudinal axis being 

 the longest. Its outer lip is angular through the shallow notches, which cause the 

 longitudinal keels. The inner lip is straight and not reflexed. H. 37 mill., br. 29. 



A great number of specimens has been found at Samsugn in Othem and also a 

 few in Martebo, in the limestone of Kyrkberget, Wisby, and on Galgberget near Wisby. 

 Thei'e is a more slender variety from Klinteberg, small, with the lamelliE more nu- 

 merous and crowded and the umbilicus narrow, reduced to a slit. 



2. TroclLonema muricatum n. 



PI, XVIII fig. .52—53. 



Shell turriculate, acuminate, upper whorls rapidly increasing in size. Whorls six, 

 angular, body whorl with four large keels, the uppermost around the umbilicus. They 

 are lacerated with broad, acuminated points at regular distances all round. Each of 

 them is, as it were, a complex of the folded edges of several transverse lamellte, which 

 have a nearly straight direction. The aperture is elongate, angular through all the 

 keels in the outer lip. The inner lip is curved and thin. The umbilicus is wide and 

 open. H. 14 mill., br. 12 mill. A single specimen has been found in the middle li- 

 mestone strata of Hoburg. 



In the list of the distribution of the species I had placed this shell in the ge- 

 nus Eunema Salter, but I now find, on closer consideration, that it cannot be kept 

 there, but rather corresponds with Trochonema. 



Gen. CRASPEDOSTOMA gen. nov.') 



Shell (/lobular, naticoid, commonly with transverse lamellar ribs. Aperture circular, 

 enclosed within an eriormonsly enlarged and thickened border, formed by successive, thin 

 strata, in the superior, inner corner elongated in an acute sj^ur and a smaller, corresponding 

 one in the inferior corner. The inner lip is bifurcated. The umbilicus is deep and narrow. 



') A'paa/ttdoj', collar, atuJfia,. mouth, aperture. 



