26 Transactions. — Zoology. 



distinct lobe (about 8 mm. long) on tbe 14th ray, and the 

 absence of anything of the kind on the loth, allows of a clear 

 distinction being drawn between the crest or " first dorsal " fin 

 and the "second dorsal," although the adjacent rays being 

 united by membrane, there is, strictly, only one continuous fin. 



A comparison of PL V., fig. 1, with Cuvier's figure (7, 

 plate xxiv., fig. 6) shows that the only difference of importance 

 between the two is that the second nuchal in the latter has 

 seven rays instead of nine, and that the terminal lobes are 

 represented as much larger than in my specimen. 



In the first nuchal the pink membrane uniting the rays was 

 marked with small circular spots of a deep crimson colour, 

 (about 2-3 mm. in diameter,) and arranged in a single row in 

 each membranous interspace. Examined microscopically, these 

 were found to be produced by aggregations of well-marked sub- 

 circular chromatophores, having interspersed among them 

 branched black pigment-cells. 



In the second nuchal each ray with its membrane was 

 marked with nearly equidistant crimson blotches, about 8 mm. in 

 diameter, generally occurring in the wider parts of the wavy 

 membrane. These also contained both red and black chroma- 

 tophores ; the former faded considerably after two or three days, 

 the spots then appearing of a dull grey colour. 



These large patches of red are shown in Cuvier's figure ; but 

 the small spots of the first nuchal are not indicated either in that 

 or in any other figure with which I am acquainted. 



All the descriptions and figures of the crest of Regalecus with 

 which I am acquainted can be accounted for on the theory 

 that it had, when uninjured, the characters described above, 

 with the single exception of von Haast's. He states (3, p. 248) 

 that, in R.pacificus, the 2nd and 7th rays were perfect, and were 

 respectively 7 and 7*75 inches long ; he also says that the 3rd, 

 4th, and 5th rays were nearly as thick as the first, and that all 

 were beset with minute upwardly-directed hooks on the anterior 

 and posterior edges. 



(e.) The skeleton. — This agrees in all essential respects with 

 that of the Moeraki specimen, the only important difference 

 being in the number and position of the ribs. In the Moeraki 

 specimen there were ribs on the 8th-25th vertebrae inclusive, 

 and in Liitken's Faroe Islands specimen (5 and 6) on the 8th- 

 24th. In the present skeleton the Gth vertebra has a rib on the 

 right side only; from the 7th to the 20th there are well- 

 developed ribs, and rudiments on the 21st-23rd. 



Both pelvic (= ventral) rays were broken off short, but 

 attached to one of them by a shred of membrane there was, as I 

 am informed by my assistant, Mr. Jennings, a bony rod about 

 6 inches long, of the same thickness as a pelvic ray, curved at 

 its proximal end, and fringed with membrane. The fact of the 



