ACARINA FROM THE JUAN FERNANDEZ ISLANDS 601 
Shape broadly pyriform, the posterior margin being almost semicircular. 
The dorsal side is very highly arched, the greatest height being almost equal 
to the width and placed far backwards in the posterior half of the body from 
where the surface slopes downwards backwards very steeply and forwards in 
an even curve (figs. IOI—103). 
The sides of the propodosoma are very sligthly concave and meet at an 
angle of 90 degrees. 
‘ Propodosoma so completely fused with the hysterosoma that not even 
a trace of the suture is seen. No traces of lamella are to be seen on the 
dorsal side of the propodosoma but at the sides in the posterior half there are 
horizontal blades, which are triangular in outline, tapering gradually forwards. 
Are these structures really to be interpreted as true lamelle, although 
their position is so different from the typical one? OUDEMANS who discusses 
this question (1917, p. 4—5) holds the view that they are and finds support 
ore A 
oe 

101 102 103 
Figs. 101—103. Galumna pacifica n. sp. 
to1. Lateral view. 102. Dorsal view. 103. Ventral view. 
for this in the fact that their anterior ends are shaped as small but distinct 
cusps. 
In the present species, however, there are no such cusps nor are the 
hairs homologuous to the lamellar hairs inserted near the anterior ends of the 
»pseudolamellaz». On dissecting the rostrum we find that the lamellz continue 
as low but sharp ridges bent downwards in an even curve along the sides of 
the propodosoma (fig. 104). 
The interlamellar and lamellar hairs are very small and inconspicuous 
(fig. 104), as are also the rostral hairs. The latter are inserted in the middle 
of a thin blade, forming the anterior edge of the rostrum and their pores con- 
tinue as narrow canals to the base of the rim exactly as is the case in some 
Uropodide, where the edges of the body also form thin blades. 
In the middle of the anterior edge of the rostrum there is a sharp tooth 
in front of which there is a square depression. 
The structure recalls vividly that described by SELLNICK (1925, p. 81, 
fig. 3) on Stsctozetes(?) medialis, and it may be that it is a not uncommon 
feature amongst the Galumnine, although hitherto overlooked. 
Behind the thin plate the rostrum is finally transversally striated. 
The pseudostigmata (fig. 105) are almost hidden underneath the base 
