20 IIINDE, ANNELIl) REMAINS FROM SU.UKIAN OF GOTLAND. 



Arabellites coiiciumis, n, Pl. 3, fig. 54. 



Jaw triangulär in ontline, concave iu the central portion; 

 tlic front margin is thickencd and extended obliquely down- 

 wards into a short cnrved shank, below this tlic lateral mar- 

 gin is geutly curved. The free lateral margin is arclied and 

 has tlie edge curved över below; it carries a series of 12 co. 

 nical pointed recurved denticles, the three anterior of these 

 are in the same plane as the plate ; those following on the 

 curved edge are at right angles to it. The under surface is 

 hollow nearly the entire length of the jaw. Length 0,6 3 mm. 

 width 0,2 9 mm. It is a rare form, and difFers from the pre- 

 ceding principally in the character and position of the denticles. 



Locality. Wisby. 



Arabellites ferox, n. Pl. 3, figs. 55, 55a. 



Compare Arabellites crenidatiis. Hinde. Quart. Jour. Geol. Soc. Vol. 

 35 p. 379. Pl. 19, fig. 9. 



Jaw plate triangulär with a stout, nearly straight shank 

 projecting at right angles from the anterior margin. The end 

 of this shank, in perfect examples, has a slight iucurved pro- 

 cess. The outer lateral margin is nearly straight, on the free 

 margin are five very prominent claw-shaped denticles, between 

 which are similar smaller ones. The under surface of the plate 

 is hollow. Length along the free margin 0,6 5 mm.; width 

 to the end of the shank 0,6 mm. This jaw is of the same 

 character as A. crenulatus from the Cincinnati series of To- 

 ronto, and difFers therefrom mainly in the form and position 

 of the denticles. 



There are other jaws evidently of the same character as 

 the above, but difFering in detail sufficiently to be regarded 

 as varieties. It seems probable that these minute forms corre- 

 spond to the smaller dental plates (Säge-platten) of the exis- 

 ting genus Arabella. 



var. a. Pl. 3, fig. 56. In this form the shank is conical 

 and slightly curved; the anterior tooth is relatively very long, 

 straight, conical and pointed, there is a minute denticle in front 

 and four behind it, the lower part of the jaw plate is wanting. 



var. b. Pl. 3, fig. 57. In this variety the shank is short 

 and slightly curved inwards, the free margin is slightly arched 

 and carries 7 conical, pointed, slightly curved denticles. The 

 length and breadth nearly cqual, about 0,33 mm.. This variety 



