112 Part TWI.— Twenty-third Annual Report 
Habitat.—Taken from a sturgeon, Acipenser sturio, captured about 
16 miles S.E. by E. of Aberdeen and brought into the Aberdeen Fish 
Market, December 29, 1904. The same species of Dichelestium has also 
been found by my son, Andrew Scott, on the gills of a sturgeon 
captured near Barrow-in-Furness, Lancashire. I am indebted to Mr, 
Bowman of Aberdeen for this further addition to the marine copepod 
fauna of Scotland. 
The structure of the mouth organs, and especially of the mandibles, 
indicates a close relationship of Dichelestiwm with the Caligid, 
Genus Anthosoma, Leach (1816). 
Anthosoma crassum (Abilgaard). Pl. v., figs. 15 and 16. 
1794.  Caligus crassus, Abgd., Mém. de Copenhagen, Act. Soc. 
Nat. Havn. 
1837. Anthosoma Smithi, Kroyer, Naturh. Tidsskr., 1st B., p. 
295, Tab. ii., figs. 2 and 2a (9). 
1850. Anthosoma Smithi, Baird, Brit. Entom., p. 296, pl. xxxiil., 
fig. 9. 
1861. Anthosoma crassum, Steenstrup and Liitken, Bidrag til 
Kundskab, p. 397, pl. xxii., fig. 24 (6). 
This interesting species was found on a shark, supposed to be a 
Porbeagle shark, Lamna cornubica, captured off the coast of Scotland by 
one of the trawling steamers that make only short runs from Aberdeen. 
The steamer, which captured the shark in October 1904, is one of those 
belonging to Mr. Davidson, Aberdeen, and is locally known as a “ short 
tripper.” Two specimens of the Anthosoma were obtained ; one of them 
is a female with ovisacs, the other, which is smaller, is probably a male. 
The drawings, figures 15 and 16 on plate v., represent a dorsal and 
ventral view of the female. This specimen measured about 15 millimetres 
exclusive of the ovisacs, and about 62 millimetres—nearly 24 inches—to 
the extremity of these appendages. 
The female, which is tolerably elongated, appears, when seen jrom 
above to be of an ovate outline; it is narrow in front, and a brownish 
horny shield, which gradually expands towards the posterior end, covers 
the head and a considerable portion of the thorax ; an obscure constric- 
tion marks the junction of the head with the thorax ; two large foliaceous 
elytraform, circular plates, the inner margins of which partly overlap each 
other on the dorsal aspect, cover entirely the remaining portion of the 
thorax not covered by the dorsal shield, and also the abdomen and furcal 
joints. These plates are ornamented by numerous minute scattered 
punctures or depressions, as shown in the drawing (fig. 15). 
The antennules are short, slender, and composed of six joints which are 
very sparingly setiferous; but the antenne—described by Baird as the 
first pair of footjaws—are strong and powerful ; they are longer than the 
antennules and composed of three joints, and armed with strong, terminal, 
hook-like claws. 
The first maxillipeds are slender and feeble, and appear to consist of 
three joints; they are provided with a small, terminal, claw-like spine. 
The second maxillipeds are short, very stout and powerfully clawed. 
The thoracic legs are in the form of thin and broadly foliaceous plate, 
each having a distinct notch on the inner margin. 
‘he abdomen is short and the furcal joints narrow and moderately 
elongated, as in figure 16, which shows the ventral aspect of the 
specimen, i 
The shield is of a chitinous texture, of a brownish colour on the sides, 
i ad pe 
