326 General Notes. [March, i 
searched no Unionidæ were found. It is not improbable that — 
the Margaritana margaritifera made its advent during that — 
interval ; its occurrence upon this sea-girt and isolated island — 
separated from the main land by at least twenty miles of — 
open water, is an interesting fact, and presents a problem in | 
the distribution of fresh-water shells, which only the methods of 
Darwin can surmount. The occurrence of the form falcataof — 
Gould in the waters of Oregon, the occurrence in the streams 
emptying into Columbia, and into Puget sound, as recorded 
by Cooper; the localities recorded by Carpenter, east of the Rocky | 
mountains ; and the known high range of the species in Europe, 
make its occurrence in the intermediate portions of the 
possessions not improbable, and I confidently look for it in these | 
waters, when they are more fully examined.—A. F. Gray. 
valuable material for this work, and has with great evident pains 
and throughness worked out the characters of these Myriopods, : 
the remains of which belong to four genera and twelve species. | 
He regards the Myriopods as an “ order,” and the Chilopoda and 
Diplopoda as“ suborders,” and proposes for the group of Carbon 
ferous Myriopods under consideration the term Archipolypott 
considering them as constituting a group equivalent in rank to 
the Diplopods (or Chilognaths). r Be 
The Archipolypoda are thus characterized ; “ Paleozoic Myr = 
apods, with a fusiform body, largest near the middle of the at a 
terior half or third, the head appendages borne upon a single a 
segment; each segment behind the head composed of a ae 
dorsal and two ventral plates, the dorsal of nearly uniform lengh 
superiorly and inferiorly, occupying most of the sides as | a : 
the top of the body; destitute of foramina repugnatora © 
divided into ridged anterior and flat posterior portion, the - natal : 
provided with longitudinal rows of spines or tubercles; thee 
plates occupying the entire ventral portion, each having gr 
long jointed legs, and furnished outside of them wit} © — 
spiracles, the mouth transversely disposed.” é rather 
Having been recently studying the Lysiopetalide, 4 afte 
aberrant and synthetic family of Chilognaths, we hara ay 
; reading Mr. Scudder’s memoir in order to ascertain pee 
lation to his Archipolypoda, felt obliged to dissent from * 
his conclusions, though not doubting the evident igre 
clearness of his descriptions of the remains upon which his 8°” 
and species are based. eo 
`The above quoted definition will apply in some points © 
