Genus of Loirer Helderherg Ostracoda. — Ulrlch. 203 
each end. Right valve with a faint dorsal overlap, a rather small 
subterminal anterior spine, and behind it a thin erest-like longitud- 
inal ridge situated about midway between the center of the valve 
and its dorsal edge. 
This is the onl}- species of the genus of which the two valves 
have been found in conjunction. They are so different that if 
found separate they would scarcely have been referred to the same 
species. Indeed, the spineless left valve would most likely have 
been regarded as Bythocypris. The two valves are known also of 
B. carinata and B. iKiciciiIa, but in these the anterior spine of the 
left valve is merely somewhat smaller than tluit of the right, while 
the B. ovata, of which the left valve only is known, this spine is 
very well developed. B. suhfumitJa, known only from right valves. 
is evidently a related form, and it is possible that in it too the 
left valve is spineless, Avhich may account for its non-recognition. 
Formation and locaJitii: Same as preceding. 
Type picked from fine residue sent me by ^Ir. Chas. Schucliert, and 
now in my cabinet. 
Beecherella navicula, n. sp. 
PLATE II, FIGS. 8 AND 9. 
Size of left valve: Length from extremity of spine to posterior 
margin, 3.4 mm.; hight, 0.7 mm. 
Valves elongate, boat-shaped, the dorsal and ventral margins 
sub-parallel, the former long, gently convex, anteriorly drawn out 
into a long spine projecting forward and a little upward like the 
bowsprit of a boat; posteriorly bending down into the sharply 
rounded posterior margin. Anterior end sloping backward from 
the base of the spine into the ventral edge. The latter is straight 
in the middle, and genth" curved upward behind. Surface mod- 
erately convex, the dorsal slope the most abrupt. The spine of 
the right valve slightly stronger and longer than that of the left. 
On the inner side the dorsal edge is thickened, especially in 
front where it forms the projecting spine. Running nearly 
parallel with the anterior edge a ridge, quite distinct in the left 
valve, but much less so in the right, is to be observed. From the 
nature of the parts forming the anterior half of the valves it 
appears that when joined and the carapace closed an opening must 
exist just beneath the spines. 
There is little prol)ability of confusing this with any of the 
