Pemphix, Glyphea, and Areosternus. 809 
VII. The Genus Glyphea compared with the Genus 
Areosternus. 
We have just seen that very probably the genus Pemphix 
is the stock, the origin, of the genus Glyphea. Now we shall 
seek the existing representative of this genus; we wish to see 
whether a form of Macrurous Crustacean analogous to the 
fossil genus still exists in the present creation. For this pur- 
pose let us compare the genus Glyphea with the genus Areo- 
sternus, De Man. 
In the first place as regards the differences. 
The surface of the cephalothorax of most Glypheew is 
adorned with tubercles, in some species (Glyphea Heeri, 
Opp.) with hollow points or with small holes, sometimes with 
spines (Gilyphea Miinstert), and in some species it is even 
almost entirely smooth (Glyphea major, Opp.). The tubercles 
are very often situated upon projecting lines, so as to form 
beaded rows, as may be seen in Glyphea Regleyana; among 
the specimens of Glyphea Lundgreni we also find some that 
are smooth. 
The surface of the cephalothorax of Araosternus Wienecket, 
De Man, is adorned with a multitude of rugosities or very 
slightly elevated tubercles, broad and flat, which bear small 
tufts of hair of a yellow colour. M. De Man says the cara- 
pace does not bear spines, as in the Palinurt, but the entire 
surface is covered ‘“‘ with numerous small transverse tufts of 
very short yellow hairs, a few longer hairs being scattered 
among them.” In this point, therefore, there is no very great 
difference between the Glyphee and Arcosternus Wienecket. 
Another difference consists in the presence of a protective 
lamina or scale in the Glyphew and the complete absence of 
this organ in Are@osternus. ‘This scale is greatly developed in 
most Gilyphee. M. Oppel says (Paliont. Mittheil. p. 56), 
“ Although this movable scale is not often met with, it appears 
nevertheless that it must have existed; for 1 have found 
it in several species of Glyphea, and especially in the well- 
preserved specimens. It is narrow and pointed, and does not 
attain the length of the peduncles of the outer antenne.”’ 
Although von Meyer says that Glyphea gratiosa (his Selenisca 
gratiosa) does not possess a movable scale, yet it may be 
that the specimen had been provided with such an organ 
and had lost it. Areosternus, on the contrary, does not 
possess this protective plate; M. De Man says “ an antennal 
scale is wanting.” 
Another difference is observable in the lamine which form 
_ the caudal fin. The external lamine of the Glyphee are 
