240 NUDIBRANCHIATA COLLECTED IN THE NORTH SEA. 



The specimen was living upon a colony of Botryllus, which was 

 attached to a large tube of Sahella pavonina, and upon which A. 

 digitntum was growing. The animal lay in a depression eaten into the 

 colony, to which it approximated very closely in colouration. 



IDALIELLA ASPERSA (A. & H.). 



Voyage XCIII. Station 77. Off Holy Island. Lat. 55° 44' N. Long. 

 1° 40' W. 32 fathoms. 1 specimen. 

 In all respects resembled the specimen described by Alder and 

 Hancock. 



ANCULA CRISTATA (Alder). 



Voyage XCIV. Station 2. N.E. of Sherringham Bank. 11 fathoms. 1 

 specimen. 



Colour a very transparent wliite ; the orange line on the keel very 

 faint. 



The linear appendages surrounding the branchiae tipped with opaque 

 white in about half their number, the rest with the normal yellow 

 tip ; they were very irregular in length. 



