a 
) 
53 Messrs. I’. and A. Scott on some 
angles of the same joints are furnished with a long slender 
seta; the secondary branches are small and bear each four 
sete on the outer margin and apex, the apical seta being 
longer than the others, while the upper two are small (fig. 22). 
Caudal stylets short ; the end of each stylet is prolonged 
interiorly into a stout spiniform process, and bears a few sete 
exteriorly (fig. 24). One ovisac, with a number of mode- 
rately large ova. 
Male. The male closely resembles the female in general 
form, but the anterior antenne are eight-jointed and strongly 
hinged, the second joint is much longer, and the third and 
fifth shorter than any of the others. ‘The fifth pair of thoracic 
feet are nearly as in the female; the sixth pair of appendages 
(the appendages of the first abdominal segment) are small, 
subquadrate in outline, and are each armed with a stout spine 
and two sete on the apical margin, as shown in the drawing 
(fig. 23). 
Habitat. In pools near low-water on the shore at Mussel- 
burgh, Firth of Forth ; frequent. 
Remarks. ‘The posterior foot-jaws with their extremely 
long terminal claws form a prominent character in this 
species and one by which it was readily distinguished from 
the other Copepoda among which it occurred in the shore- 
gathering from Musselburgh. The peculiar appearance of tire 
caudal stylets which is represented in the full-sized drawing 
(fig. 12) is also a marked character; the sete, as shown in 
the drawing referred to, extend upwards at an obtuse angle 
from the terminal spine, to which they seem to be attached 
when viewed laterally ; and this peculiar appearance was 
observed in all the specimens obtained. ‘The structure of the 
first pair of swimming-feet resembles somewhat that of the 
same pair in Mesochra Robertsoni, Brady, and in some 
species of Attheyella. 
Mesochra MacIntoshi, sp. n. 
(Pl. V. figs. 26, 27; Pl. VI. figs. 1-7.) 
Description of the Species.—Female. Length *6 millim, 
(js of an inch). Body elongate, cylindrical, very slender. 
Anterior antenne rather longer than the first cephalothoracie 
segment, eight-jointed, the penultimate joint being con- 
siderably shorter than any of the others, as shown by the 
formula— 
Proportional lengths of the joints. . 1] .22.16.11.83. 
Number of the joints ............ oS ere ie lee 5: 
oe 
Ne 
