514 H. p. KJERSCHOW AGERSBORG 



erstreckt.' From this one might infer that the author was 

 describing the species from preserved material ; for the hver 

 is brown in colour as a rule, and from it Melibe obtains most 

 of its colour. The internal organs, however, may be partly 

 seen through the body- wall in living specimens of M.leonina 

 (PI. 27, fig. 2). Gould describes the brownish ramifications of 

 the papillae as vascular ; these, however, are branches of the 

 liver. He also says that the tentacles are ' destitute of vena- 

 tion ', referring no doubt to the hepatic branches which 

 are very abundant everywhere. The hepatic branches are 

 less abundant in the tentacles but they are not wholly 

 absent. 



1. The Head or Veil. 



The head of M . 1 e o n i n a is very prominent because of its 

 exceedingly large veil or hood. This is modified by two rows 

 of cirrhi (Pis. 27, 28, tigs. 1, 3, 10, 17) which fringe its edge, and 

 by a pair of ear-like tentacles (PL 27, figs. 1, 2, 3). The cirrhi 

 of the outer row are much larger and far less in number than 

 those of the inner row. The average, taken from a number of 

 specimens, was 48 in the outer row, and 123 in the inner row, 

 or 2-56 small cirrhi to 1 large. The outer row does not extend 

 entirely around the rim of the hood, but, in an animal about 

 6 centimetres long, terminates about 1 centimetre from the 

 mid -ventral line. The inner row extends all around the peri- 

 phery of the hood, although the last three cirrhi, on each side 

 of the mid-ventral, are rudimentary (PI. 28, fig. 17, Icr, Icr^). 

 A large veil or hood, except in M. ocellata Bergh (18906), 

 is a common thing for Melibe Gould (1852), Alder and 

 Hancock (1865), Bergh (1875 &, 1902, 1904), Eliot (1902). 

 In M. bucephala, Bergh (1902), ' The edge of the head is 

 rather thin above and almost smooth : its outer parts, however, 

 are thick, inwardly somewhat refolded or convoluted, and 

 provided with several, mostly perhaps about five, close-set 

 series of cirrhi, which are displaced among each other ; these 

 cirrhi are conical, somewhat constricted at the base, the inner- 

 most ones are the larger, toward the outside they decrease 



