BIIIANG TILL K. SV. VET.-AKAJ). HANDL. BAND. 7. N:0 5. 17 



to tlie anterior hook, but tlic cavity is inclosed by a flattened 

 convex plate. The specimens vary between 0,7 and l,i 

 mm. in length, and from 0,2 to 0,3 mm. in width. Thcy 

 vary slightly from the typical example of the species from 

 tlic Cincinnati series of Canada, but tlie variations are not 

 greater than those wliich are present in some of the Cana- 

 dian specimens. There can be no doubt of the similarity of 

 theso jaws to the »pincers» in the existing Arahella. Tho 

 jaws which were figured in the unpublished plate of sihirian 

 fossils, by Prof. Angelin (figs. 20 to 23) appear to bclong to 

 this species. The examples are somewhat rare. 

 Locality. Wisby and Fröjel. 



Årabellites fastigiatus, n. TI. 2, lig. 45. 



This jaw is in outliuc similar to the preceding; but it 

 possesses a strong ridge which extends from the postcrior 

 cxtremity across the plate, and is then continued forwards 

 on the outer lateral margin quite to the end of the hook. 

 In front of the ridge, and contiuuous with it, is a round(!d 

 furrow. The free margin has a series of 12 denticles, the 

 "'.terior four are compressed, triangulär and spring from tho 

 margin of the plate, the next following are on the edgc of 

 a small vertical ridge. The under surface is concave and opcn 

 as far as the junction of the hook with the plate. Length 

 1,2 8 mm.; width 0.4 m. m. The form is rare ; biit both right 

 and Icft jaws are present, and alike exhibit the distinctivc 

 feature of the longitudinal ridge and furrow. 



Locality. Wisby. 



Årabellites contractus, Hinde. Pl. 2, ligs. 46, 46 a. 



180. Årabellites spicatus, var. contractus, Hinde. Quart. Jour. 

 Geol. Soc. Vol. .36, p. 375. Pl. 14, f. 14, 15. 



Jaw plate oblong, convex, widest in front and extended 

 forwards into a stout hook which is obliquely curved inwards. 

 The posterior margin obliquely truncate with a spoon shaped 

 depression close to the dental ridge. The outer lateral margin 

 gcntly curved and slightly inflated. There are about 10 re- 

 curved conical denticles on the edge of a slight ridge which 

 is nearly vertical to the plate. The under surface cxhibits in 

 the lower half a wide open concavity, bordered by convex 

 ridgcs; the front portion is arched ovcr and convex. Total 

 length 1,1 ; width O, hl mm. The specimens vcry closely rc- 



2 



