18 ^ T UDiBRANCHIATA. 



and marked with about 30 raised white lines or stripes, which 

 are irregularly nodulous and alternately larger ; at the sides 

 they are broken up into small tubercles and crowded : tenta- 

 cl-es and gills yellowish : foot whitish, with the sole of a paler 

 hue than the rest of the body. L. 1. B. 0-4. 



Habitat : My friend the late Mr. Barlee dredged on 

 the coast of Shetland a single specimen, which I ex- 

 hibited at the Birmingham Meeting of the British 

 Association in 1849. The Rev. R. C. Abbes procured 

 another specimen from a fishing-boat at Whitburn, co. 

 Durham. South-western coasts of Sweden (Loven and 

 Lilljeborg); Christianiafiord (Asbjornsen) ; Hornbsek 

 in Zealand (Horring, fide Bergh) ; depths 7-40 f. 



Diphyllidia undulata of Meckel (_D. lineata, Otto), to 

 which these specimens were at first considered to belong, 

 is not uncommon in the Mediterranean. It differs 

 from the present species in being of a larger size and 

 proportionally very much broader, as well as in its 

 colour, which varies from whitish to the darkest black ; 

 and the stripes in that species are more numerous, 

 nearly regular, and equal in size. Bergh has also 

 pointed out a distinction as regards the masticatory 

 apparatus. 



Order V. NUDIBEANCHIA'TA, Cuvier. 



Body slug-like, soft : mantle very large, covering the back 

 and sides : tentacles consisting of one pair or two, which are 

 placed on the front portion of the mantle : eyes sessile, im- 

 bedded in the skin behind the tentacles, at their base ; they 

 are conspicuous in the young, but not always discernible in 

 the adult : foot extensile : r/ills or branchial processes, when 

 present, always external, placed upon the back or sides, sym- 

 metrical, and arranged in plumes, tufts, or papillae ; in the 



