OSTRACODA. 683 
Moorea? perplexa.] 
MoorkA ? PERPLEXA, 2”. Sp. 
PLATE XLVI, FIGS. 17 and 18. 
SizzE.—Length 0.85 mm.; hight 0.62 mm.. 
The figures present such a remarkable valve that I am quite unable to account 
for its peculiarities. Unfortunately the original of the drawings, which were made 
four years ago, has been mislaid or lost, so that [am obliged to publish them without 
a final verification of the characters shown. It may really be a Moorea, but I doubt 
it. Orit may be related to Placentula. With more material its affinities may become 
clear, and it is the hope that collectors will search for and perhaps succeed in 
rediscovering the species, that has induced me to retain it in my report. . 
Formation and locality.—Middle third (Rhinidictya bed) of the Trenton shales, near Fountain, 
Minnesota. ‘ 
Genus MacroNnoTELLaA, n. gen. 
Carapace convex, semicircular or semiovate, with a long, nearly straight, hinge; 
valves equal, full centro-dorsally, without ridges ora sulcus, but exhibiting a smooth 
subcentral spot where the ornament is omitted; surface, in the only species known, 
coarsely punctate. 
Type: WM. scofieldi, n. sp. 
I saw no way to escape the responsibility of erecting a new genus for the fol- 
lowing species without forcing it into one of several that I am fully persuaded ought 
not to receive it. The long hinge, semicircular outline, and almost perfectly equal 
ends, rendering it difficult to distinguish one from the other, give it an expression 
peculiarly its own. Kirkbya permiana Jones, it is true, has a somewhat similar form, 
but like all the species of that genus, it has also a marginal ridge and a subcentral 
pit, neither of which are present in the species under consideration. Still, the 
smooth spot mentioned above probably represents the pit of Kirkbya, and it is with 
this genus that I think the affinities of Macronotella lie rather than with either 
Aparchites or Isochilina. The Isochilina rectangularis Ulrich (Jour. Cin. Soc. Nat. 
Hist., vol, 13, p. 182; 1890) from the Devonian at the falls of the Ohio, may be 
congeneric with M. scofieldi, there being some similarity in their outlines, but as 
“the surface of the Devonian form is perfectly smooth and not inflated centro- 
dorsally, I hesitate to say it is. 
