612 



NATURALIST'S GUIDE TO THE AMERICAS 



8. PANAMA 

 By E. A. Goldman and James Zetek 



I. INTRODUCTION (e. a. G.) 



The brief account of Panama here 

 presented is largely an abstract from 

 published results (Goldman, 1920) of 

 field investigations by the author in 

 1911-1912 in connection with the biologi- 

 cal survey of the Panama Canal Zone, 

 undertaken by the Smithsonian Insti- 

 tution in cooperation with the Biological 

 Survey and other government depart- 

 ments, and supplemented by informa- 

 tion gathered from various sources. 

 The field work was centered largely in 

 the Canal Zone, but extended to extreme 

 eastern Panama. 



II. GENERAL FEATURES AND ORIGINAL 

 BIOTA (e. a. G.) 



A. Topography 



The narrow intercontinental land 

 mass forming the Republic of Panama 

 extends in a sigmoid curve from east to 

 west between the meridians of 77° 15' 

 and 83° 30' west from Greenwich and 

 parallels 7° 10' to 9° 40' of north latitude. 

 It varies in width from less than 50 mi. 

 at the Canal Zone and at the constric- 

 tion between the mouth of the Rio 

 Chepo and the Bay of San Bias to over 

 100 mi. at the Azuero Peninsula. Ex- 

 cept for the Chiriqui Lagoon the north- 

 ern shore line forms a nearly undented 

 S-shaped curve. The southern coast 

 line, on the contrary, is very irregular. 

 There are numerous inlets or baj^s, and 

 several peninsulas form prominent sa- 

 lient features. The smaller bays are 

 mainly the tidal estuaries of the numer- 

 ous rivers, some of which are of large 

 size. The estuary of the Rio Tuyra 

 permits small steamers to ascend to 

 Real de Santa Maria, about half the 

 distance from the outer shore line across 

 to the Atlantic Coast. The most con- 

 spicuous projection, the Azuero Penin- 

 sula, in broadly extended outline, 

 bounds the Gulf and Bay of Panama on 

 the west. Another prominent feature 



of the southern coast is the Burica 

 Peninsula, a prolongation of the Ser- 

 rania de Carones, territory in dispute 

 between Panama and Costa Rica. The 

 largest outlying land area is Coiba 

 Island, of slight elevation, off the south- 

 western coast. Numerous small islands 

 lie close to the adjacent coast, of which 

 some of the more important are Cebaco, 

 and Leones islands in Montijo Bay, and 

 farther west Insolita, Espartal, Brava, 

 Parida and Sevilla islands. The second 

 largest island is San Miguel, or Rey 

 Island in the Bay of Panama, which with 

 smaller neighboring islands form an 

 archipelago known as the Pearl Islands. 

 These islands are rather low, but rugged 

 in contour, with eroding coast lines like 

 those of parts of the adjacent mainland. 

 Small islands are numerous along the 

 northern coast, but aside from the 

 low, forested archipelago separating the 

 sea from Almirante Bay and the Chiriqui 

 Lagoon, are relatively unimportant. 



The general land surface is hilly and 

 irregular, but the only very high moun- 

 tains are in the extreme western part, 

 where an extension of the highlands of 

 Costa Rica crosses the international 

 boundary about midway between the 

 two oceans and culminates at about 

 11,500 ft. in the volcano of Chiriqui. 



The rather ill-defined backbone of the 

 Isthmus is divided by comparatively 

 low passes into several irregular sections 

 in which steep, but not usually precipi- 

 tous, mountain ranges reach varying 

 elevations, in few places exceeding 

 5000 ft. The Serrania del Brujo, begin- 

 ning near the Atlantic coast a few miles 

 east of Colon, rises near Porto Bello to 

 3000 or 4000 ft., and partially encircling 

 the Chagres River Valley joins the con- 

 tinental axis near Cerro Azul, a mountain 

 about 3000 ft. high on the crest between 

 the Chagres and Pacora river valleys. 

 A short distance east of Cerro Azul 

 are transcontinental gaps probably less 

 than 1000 ft. in altitude where the head- 

 waters of the Rio Mamoni interdigitate 

 with those of streams flowing north into 

 the Gulf of San Bias. Farther east the 

 long, narrow curved Isthmian backbone, 



