196 
N’ictiolls — Tu:o New Phrcaioicids. 
re-curved, with u forked aj)icul hook and more ])roximal curved 
pectinations (hg’. 28c); tlie scaly surface is well seen liere. 
The (/iiathopod (PI. XXVJI, hg. 20) is of the usual type, the 
propod unusually strong, tlie palm straight, extending along the 
entire posterior border of the joint; both ischios and nieros are ex- 
panded and })roduced anteriorly into a lol)e which is prolonged by a 
stout spine, the lobe of the moros being directed almost proximally. 
In the three succeeding a])i)endages, also, these joints are notably 
produced, such considerable development of the meros being met 
with, so far as I can discover, in no other extant species of tlie 
l^hreatoicidea. In the fossil form P. teianamaftensi.s. however, a 
similar condition is ch'arly shown, Chilton (1918), calling ]mrticular 
attention to this fentTire (l.c.. p. 368). 
The fourth peracopod (PI. XXVII, fig. 21) is sub-clielate in the 
male, as in all s])ecies of Ph r('at(dcus, dilTeriiig in this from Autphi- 
y(.j>us. It is noteworthy that in the jterfectly jireserved fourth 
p. raeopod of P. iriauiuixitteiisis there is no suggestion of a sub- 
chelate condition, but the im])ression may, of course, have been that 
of a female. 
The fifth, sixth, and seventh peraeopods (PI. XXVII, figs. 17, 22} 
show a rounded basos with a marned posterior ])late-like ex{)ansion 
and a similar ex])ansion is developed on ischios anil meros of both 
the liindiM' a}>])endages. In the fossil form a similar ex])ansion is 
indicated (though less developed) in Chilton’s figures 1, 2, 3, 7, and 
10, and it is noteworthy, also, that in this s]>ecies the ischios is 
relatively much shorter than is usual in this genus. In this extinct 
form, too, it may 1)(> noted that the segments seem to have had a 
much more uniform length. 
The male apjiendage (PI. XXIX, fig. 38) is a curved structure, 
relativcdy short and stout, bearing a few setae on its anterior (more 
convex) border and with evident seri-ated margin. 
Pleopods. In the a])i)eiidages of the jdeon, the first point to be 
notc'd is that, in all, the two rami are a])]>roximately equal, in tne 
sens' that the endojiodite extends distally practically as far as the 
exopo iite, a condition foinnl elsewhere, so far as T can discover, only 
in A. Jatipes. Further, in all but the first of these appendages a 
large epi])odite is present. In two of the specimens examined I 
failed to find an epipodite upon the third pleopod, but the jdate is 
vei'y easily detached and possibly was lost in removal. In none of 
the sj):.cirnens examined was an epi])odite lacking from the second 
pleopo I, having there a snl)-triangular shai)e ; on succeeding a])pen- 
dages this plate is much larger and roughly quadrangular, fringed 
