PLUMTJLARIA. 151 



from the joint, which has two or three rings. "The upper 

 part of the vesicles is prolonged into a short tube, affording 

 an additional distinctive character betwixt it and PI. pin- 

 nata, which it so closely resembles," (Hassall.} 



6. PLUMULARIA CATHARINA, Dr. Johnston. (Plate IX. 

 fig. 27.) 



Hab. On old shells, corallines, and Ascidia; deep water. 

 Frequent in Berwick Bay, Dr. Johnston ; Scarborough, rare, 

 Mr. Bean; Frith of Forth, Mr. Coldstream; Isle of Man, 

 Prof. Ed. Forbes ; Howth and Lambay, Mr. Hassall ; Corn- 

 wall, Mr. Couch and Mr. Peach; Aberdeen, Mr. J. Mac- 

 gillivray ; near the Mull of Cantyre, Mr. Hyndman ; Lam- 

 lash Bay, D. L. 



Dr. Johnston says, " This equals PL pinnata in size and 

 delicacy, but it differs from it very obviously in having 

 opposite pinnae, which, instead of being arched, bend in- 

 wards, so as to render the general form of the coralline con- 

 cave, on a front view; an appearance produced by the 

 pinnse originating, not from the sides, but from the anterior 

 face of the stem." 



To be convinced of the great beauty of this elegant 

 coralline, we must see itself, or see in Dr. Johnston's 

 work the graceful figure of it furnished by his accomplished 



