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Part III. — Ninth Annual Report 
The sculpture of this exceedingly small species is like that of no other 
Lynceii. It consists of bold and obliquely curved striae, and not merely 
impressed lines, which imjvart a beautifully fluted appearance to the shell 
when the light strikes across the striae. My specimens differ somewhat 
from that figured by Norman and Brady in the work cited, in the rostrum 
being less curved — being in fact nearly straight — whereas the figuie shows 
the rostrum curving inwards considerably. My specimens agree better 
with the figure of A. pygrncea in Herrick's report. It seems to be a some- 
what rare species. 
Peracantha, Baird. 
Peracantha truncata (Miiller), 
1781. Lynceus truncatus, Miiller, Entomostraca, p. 75, pi. ii. figs. 4-6. 
1850. Percccantha truncata, Baird, Brit. Entora., p. 136, pi. xvi. fig. 1. 
1867. Lynceus truncatus, Nor. and Brady, loc. cit., p. 387, pi. xxi. fig. 9. 
1884. Pletoroxics truncata, Herrick, loc. cit., p. 112. 
This is one of the more distinctly characterised species, the posterior 
extremity of the carapace is subtruncate and armed all along the edge 
with a series of large tooth-like processes, the hindermost of which are 
directed backwards ; surface of shell divergently striated." I have followed 
Norman in retaining Baird's generic name, Peracantha.* 
Pleuroxus, Baird. 
Pleuroxus Icevis, G. 0. Sars. 
1844. Lynceus trig onellVjS, Zaddach, Syn. Crust. Pruss. Prod., p. 28. 
1861. Pleuroxus Imvis, G. O. Sars, Om. de i Omeg. af Christi., forekom. Clad., 
p. 22. 
1867. Lynceus Icevis, Nor. and Brady, loc. cit, p. 389, pi. xviii. fig. 5 ; pi. xxi. 
fig. 14. 
1884. Pleuroxus hastatus, Herrick, loc. cit., p. 108, pi. i. fig. xvi. 
This species may be distinguished from the others by the form of the 
post-abdomen, which narrows gradually towards the claws. The claws 
are furnished with two basal spines. With a low power of the microscope 
the carapace appears faintly costate, but under a moderately high power 
(J inch) the surface is seen to be reticulate, besides being finely striate 
longitudinally. 
Pleuroxus trigonellus (Miiller). 
1776. Lynceus trigonellus, Miiller, Zool. Dan. Prod. No. 2395. 
1850. Pleuroxus trigonellus, Baird, Brit. Entom., p. 134, pi. xvii, fig. 3 (feni.). 
1850. Pleuroxus hamatus, idem ibidem, p. 136, pi. xvii. fig. 5 (mas.). 
1867. Lynr^eus trigonellus, Nor. and Brady, loc. cit., p. 391, pi. xxi. fig. 11. 
1884. Pleuroxus trigonellus, Herrick, loc. cit, p. 108. 
A widely distributed species, but seldom very abundant. The post- 
abdominal claws are furnished with one basal spine. 
Pleuroxus uncinatus, Baird. 
1850. Pleuroxus uncinatus, Baird, Brit. Entom., p. 135, pi. xvii. fig. 
1867. Lynceus uncinatus, Nor. and Brady, loc. cit, p. 393, pi. xviii. fig. 9 ; pi. 
xxi. fig. 13. 
1884. Pleuroxus uncinatus, Herrick, loc. cit., p. 114. 
This seems to be widely distributed though not very common. It varies 
a good deal in the shell sculpture. There are also slight modifications in 
the form of the carapace ; the greater number of our specimens have the 
fostrum more closely appressed to the shell than in those figured by 
Norman and Brady, and in this respect they agree more closely with 
Baird's figure. The post-abdomen is similar to Norman and Brady's 
figure. 
* See Museum Normanianum, pt. iii. (1886). 
