248 BUSH 



Found on stones and shells from the Grand Banks of Newfoundland, 

 and on a fragment of shell from Devonshire, England. 



Spirorbis cancellatus Fabricius 1780. pi. xxxix, fig. 36; pi. XL, fig. 



27; pi. XLII, figs. 30-34. 



A dextral, vitreous, grooved and carinated form, associated with 

 numerous specimens of S. sulcatus Adams, is attached to a worn 

 limpet shell from Birterbuy Bay, Ireland. Small notches along the 

 edge of the base indicate the possibility of its proving to be an unde- 

 veloped or maturing specimen of S. cancellatus Fabr. not before 

 recorded from Great Britain. It may be S. conicus Fleming (1825) 

 which Morch placed as a variety of S. vitreus Fabr. 



Spirorbis communis Bosc 1802. 



No satisfactory conclusion can be reached in regard to this species, 

 owing to the very brief description and indefinite locality. The figure 

 given by Bosc represents a regularly coiled sinistral form with smooth 

 surface, similar to S. Spirorbis Linn6. 



Spirorbis corrugatus Montagu 1803, non Caullery and Mesnil 1897. 



On a stone from Birterbuy Bay, Ireland, are four species of Spir- 

 orbis. The most numerous form is of good size, sinistral, the last 

 whorl usually covering all the others, forming a central pit ; some- 

 times irregularly coiled, with the aperture turning upward. Surface 

 in perfect condition, very lustrous and smooth, but as this epidermal 

 layer is easily destroyed many of them have the surface roughened by 

 numerous transverse lines, but no spiral ones. These apparently agree 

 with Montagu's description. The dextral form sometimes having 

 spiral lines, identified and figured by Caullery and Mesnil (1897) as 

 this species, must be distinct, for which the name pseudocorrugatus 

 is proposed. The form described and figured by Langerhans (1880) 

 is also dextral. 



Spirorbis heterostrophus Montagu 1803. 



A regularly coiled, small, dextral form has the surface cut by 

 grooves and carinae which increase with age, so that fully developed 

 specimens are distinctly tricarinate, the entire surface often roughened 

 by transverse lines. Another small dextral form, which is considered 

 distinct, has two, three, or more rounded spiral threads and no 

 grooves. This one does not appear to have been mentioned by Mon- 

 tagu or others. A third dextral form has a single dorsal carina and 

 may prove to be S. carinatus Montagu or S. minutus Montagu. 



