238 NUDIBRANCHIATA COLLECTED IN THE NORTH SEA 



Several very young examples were examined, the smallest being 

 2 mm. in length ; in this specimen the dentritic processes were simple, 

 cylindrical, clavate, and incipiently branched in the first pair, which 

 was much the largest ; rhinophores plain and unbranched. 



TRITONIA HOMBERGI, Cuvier. 



This species was taken at a large number of stations. 



It appears to be generally distributed, though seldom abundant ; it 

 was especially numerous where Alcyonium digitatuvi abounded. The 

 colouration varied from white, yellowish white and grey, to light or 

 very dark brown. 



TRITONIA PLEBEIA, Johnst. 



Like the last, this species was found wherever Alcyonium digitatum 

 was at all abundant, and was generally to be found creeping about the 

 base of a colony, or between the fleshy lobes. Considerable difference 

 exists between the individuals from the white and those from the 

 orange colonies of Alcyonium ; those from the white being of a pale 

 hue, and those from the orange a warm orange-brown with darker 

 markings. 



AROHIDORIS TESTUDINARIA (A. & H.). 



Voyage XCIII. Station 59. Lat. 55° 31' N. Long. 0° 19' W. 47 fatlionis. 

 1 specimen, 



Length 45 mm. ; general colour dark greenish yellow. 



Branchite 9, with a dusky fringe Rhinophores short. Warts of 

 two sizes, low and obtuse. Mantle ample, covering the sides and foot. 

 The radula agreed with the figures given by Eliot (Journ. liar. Biol. 

 Assoc, Vol. VII, 1906, PI. xi. Fig. 2). 



AROHIDORIS TUBERCULATA (Cuvier). 

 East Hartlepool. Eocks about low tide mark. 1 specimen. 



AOANTHODORIS PILOSA (Miiller). 



Very common wherever Alcyonidium gelatinosum is at all abundant, 

 and is widely distributed. 



Varying in size from a few mm. to nearly 5 cm. in length. Usually 

 pure white, sometimes grey, and occasionally brown or dusky. Spawn 

 abundant upon Alcyonidiuiii gelatinosicm. 



