416 SPHHROMIDZ. 
followed by a slender nine-jointed flagellum. The lower 
antenne are slender, having the four basal joints slender, 
the first and second shorter than the third and fourth, 
which are equal. The flagellum is slender, and consists 
of seventeen articulations. The foot-jaws differ from 
those of the typical species, in having each of the three 
intermediate joints dilated into an internal flattened lobe, 
a character which, in conjunction with that of the short 
plates of the lateral appendages of the terminal segment 
of the body, seems to indicate a more than specific 
distinction, and which is probably also found in Sph. 
Griffithsii, which appears to be congeneric. The five pos- 
terior segments of the body have their lateral portions 
separated bya slender impressed line (indicating the basal 
division of the legs attached to each of them), and the 
hind segment of the tail is marked with two elongated 
carine ; its extremity is obliquely rounded, with a small 
notch on either side. 
We regret that the paucity of individuals which we 
have been able to examine of this and the preceding 
species, and its supposed variety Sph. Griffithsti, do not 
allow us so satisfactorily as we could have wished to 
determine the real position of the latter, which may pos- 
sibly belong to the present species, having the tubercles 
on the tail nearly obliterated. 
Dr. Leach obtained his unique specimen from Mr. C. 
Prideaux, who took it on the west coast of Devonshire. 
We possess a specimen of the species of Spheroma 
figured by Savigny in the great work on Egypt. Crust. 
pl. 12, f. 4, distinguished from Sph. serratum by its more 
elongated form, flattened triangular head, and especially 
by the semicircular notch at the extremity of the tail. 
We believe it to be British; but being unable to speak 
with precision on the subject, we have omitted to figure 
it in the present work. 
et =a 
