600 



HISTORICAL GEOLOGY. 



920. 



921. 



near Canandaigua Lake, is eight inches long. Another kind, Mesothyra 

 Neptuni H., differed little from the Portage species, M. Oceani, figured 



on page 615, and was probably nearly 

 a foot long, independent of the tail 

 spines, which add five and a half 

 inches. 



There were also Ostracoid Crusta- 

 ceans of several genera, and among 

 them the oldest known of Estherise 

 — E. pulex of Clarke. The Barnacle 

 tribe of Crustaceans 

 species. Fig. 922 rep- 

 resents a true sessile 

 barnacle of the Hamil- 

 ton, Protobalanus Ham- 

 iltonensis Whitfield, 

 and Fig. 921 two plates 

 of the pedunculate Bar- 

 nacles of the Lepas 

 family, named Turri- 

 lepas Devonicus by 

 Clarke. 



also had its 



922. 



Fig. 920, EcMnoearis punctata ; 921, 921 a, 

 Turrilepas Devonicus. Fig. 920, Beecher ; 

 921, Clarke. 



Fig. 922, Protobala- 

 nus HamUtonensis. 

 Whitfield. 



7. Insects. — Remains of Insects have been found at St. John, New Bruns- 

 wick. They are related to the Ephemerm or Mayfties; and one of these 

 is represented in Fig. 923 — the PlatepUemera antiqua of Scudder — species 

 whose larves live in the water, and which frequent moist places, and there- 

 fore stood a good chance of becoming preserved as fossils. It was a gigantic 

 species, measuring five inches in spread of wings. 



923. 



924. 



Fig. 923, Platephemera antiqua; 924, Xenoneura antiquorum. Scudder. 



Several other species of Insects have been described from the same 

 locality. One of them, the Xenoneura antiquorum of Scudder (Fig. 924), 

 while related to the Ephemerids, under the Neuropters, has some characters 

 of the Orthopters, one of which is the possession, according to Scudder, of 

 what appears to be a stridulating organ on the surface of the wing near its 

 base (see the figure), an organ for making their shrill sounds by friction. 



