Fossil Entomostraca from South America. 263 



in PI. X, Fig. 5) ; and stated that it came probably from the district 

 of Lebu. This is on the sea-coast in the province Arauca, Chili, 

 37° 36' (or 37° 39') S. lat., and is said to be on a Tertiary 

 formation, in which are seams of lignite or coal, associated with 

 shales bearing Tertiary marine shells. Stelzner intimates that 

 Philippi's researches (1878 and 1883) prove the existence there 

 of both an Eocene and a later Tertiary formation. See also Philippi, 

 " Tert. u. Quat. Verst. Chiles," 1887, p. 17. 



The little sketches in fig. 12 (11 x 8 mm.) have in their general 

 aspect the look of -£". Forbesii, being subovate, with a long, straight 

 back ; and, although the curvatures of the ends do not correspond 

 (possibly having been squeezed), the specimens shown by fig. 12 

 (reproduced in PI. XI, Pig. 2) may safely be referred to the above- 

 mentioned species. Philippi mentions that they came from Cacheuta 

 in Mendoza, and named them jE. ? Mendocina. Unfortunately, he 

 stated that they are like a " I'osidonia." Most probably by some 

 accident "Fosidonia" and "M Dahalacensis '' were erroneously 

 misplaced one for the other by the author in writing his notes 

 on these two species. 



To make the subject quite clear the following notes are necessary : 



§ VI. (2) EsTHERiA Forbesii, Jones. 



PLATE XI, Fig. 2. 



Cypridina, Burmeister, 1861, " Eeise durch die La Plata Staaten," 



vol. i, p. 77; "Descrip. Phys.," etc., vol. i, 1876, p. 262. 

 JSstheria Forbesii, Jones, " Monogr. Foss. FJstherice^' : Pal. Soc. 1862, 



p. 109, pi. iv, figs. 8-11. 

 U. Mendocina,^ Philippi, "Tert. u. Quat. Verst. Chiles," etc., 1887, 



p. 223, pi. L, fig. 12. 

 ^. Megalensis {pars), Geinitz, " Beitrage zur Geologie und Palaeon- 



tologie des Argentinischen Kepublik," II, Palaeont. Theil, 



Abth. 2; " Ueber Rhaetische Pflanzen- und Thier-Reste in 



den Argentinischen Provinzen La Rioja, San Juan, und 



Mendoza," 1876, p. 3, pi. i, fig. 5. 

 This straight-backed Jistheria is suboblong when adult (" Monogr. 

 Foss. Usth.," pi. iv, fig. 8), with about twenty-two concentric ridges ; 

 their interspaces reticulate, with about seventeen meshes from ridge 

 to ridge. In the young state (fig. 9, with 13 ridges ; and fig. 10, 

 with only seven) the shape is subcircular or subquadrate, as in 

 other young Estlierioe. The adult form (fig. 8) measures— length 

 11-2, height 7 mm. 



jE". Forbesii much resembles several other known Fstherice in 

 general shape and in style of ornament ; but there are points of 

 difference in all these cases. Some varieties of the Triassic F. ininata 

 may be alluded to : such as •' Monogr.," pi. ii, fig. 9, var. Brodieana ; 



1 The province of Mendoza, indicated by the name 3fe?tdocina, formerly belonging 

 to Chili, and so referred to by Philippi, was previously known as Cuyo, and part 

 of La Plata. It is now described by geographers as belonging to the Argentine 

 Eepublic, the mutual boundary having been settled by a treaty in 1881. The limit 

 passes along the crest of the Andes down to the Magellan Straits. 



