18 HINDE, ANNELID REMAINS FROM SILURIAN OF GOTLAND. 



semble the type forms from the English Wenlock. It is some- 

 what rare and all the specimens which I have met with are 

 left forms. 



Locality. Wisby. 



Arabellites spicatus, Hinde. Plate 2, figs. 47—49. 



1880. Arabellites spicatus, Hinde. Quart. Journ. Geol. Soc. Vol. 36 

 p. 374. Pl. 14 f. 13. 



Jaw plate sub-rliomboidal, longitudinally concave and ex- 

 tended forwards into a stout obliquely curved hook; the ex- 

 teriör lateral margin is elevated and thickened; the posterior 

 margin incurved; on the free margin is a thickened ridge ex- 

 tending backwards beyond the main portion of the plate, and 

 supporting on its edge a series of 10 stout conical recurved 

 denticles, which are nearly at right angles with the plate. 

 The under surface of the plate is hollow and open as far as 

 the commencement of the hook. A large specimen is 1,3 mm. 

 by 0,57 wide, whilst a small one measures 0,6 by 0,3 6 mm. 

 in width. It is a rare form; I have only found specimens 

 belonging to the right side of the jaw apparatus. In the Got- 

 land examples, the spur which projects from the posterior 

 margin of the Wenlock shale forms is not developed, but in 

 other respects the similarity to the typical forms is very close. 

 This jaw appears to represent the »pincers», though there is 

 no indication of any attachment to supports below, as in the 

 normal types of the existing genus Arabella. 



Locality. Wisby. 



Arabellites anglicus, Hinde. Plate 2 figs. 50, 50a, 51. 



1880. Arabellites anglicus, Hinde. Quart. Jour. Geol. Soc. Vol. 36 

 p. 275 Pl. 14 fig. 17, 



Jaw plate elongated, the ujDpcr surface longitudinally 

 concave ; the front margin curves inwards and terminates in 

 a stout curved hook which is oblique to the plate. There is 

 a stout, blunted shank which projects obliquely downwards 

 and outwards, below this the lateral margin curves to the 

 truncated posterior extremity. The free margin immediately 

 below the hook is deeply curved and miuutely crenulated, it 

 then becomes sligthly arched and carries a series of 8 stout 

 conical denticles. The under surface has an elongated curved 

 apcrture near the posterior end; in front of this the under 



