416 



GEOLOGICAL SURVEY OF THE TERRITOEIES. 



rnd/ 



Plate XXII, fig. 1, provisionally represents the freshly hatched larva 



of Arteniia gracilis, 

 which we observed at 

 Great Salt Lake, Utah, 

 the drawing having 

 been made from an al- 

 coholic specimen. On 

 comparing it with 

 Clans' figure of the 

 freshly hatched larva 

 or Nauplins of the 

 European Branchipus 

 stagnalis (iFig. 47) the 

 first anteunse are seen 

 to be much shorter; 

 the second pair with 

 much shorter and 

 smaller setse; while 

 the mandibles are 

 nearly destitute of 

 setie. Moreover the 

 body is segmented be- 

 hind the mandibles. 



Our Salt Lake Ar- 

 temia differs from the 

 figures of the Euro- 

 pean J. rfemiasaZma in 

 the shorter first anten- 

 nae; in the shorter and 

 of the 

 But 



a single larva was, however, observed, and our figure is, though a camera 



drawing, subject to future correction. 



Tig. 43. — Advanced larva of Limnadia hermanni, lettprinj: as in flf;. -,, , 



42. sh, carapace valves ; i/if, intestine ; Z, liver, mnch enlarged. After Smaller SCtcB 



Lerebouiiet. sccoud antcnnse. 



Fig. 44. — !N'auplius freshly hatched, of Apiis 

 cancriformis. s, segments IJehind the manflib- 

 iilar segment; I, liver j e, simple eye. After 

 Claus. 



Fig. 45. — Naupliua of Lepidurus 

 much enlarged. After Brauer. 



THE GENEALOGY OF THE PHYXLOPODA. 



In considering the question of the genealogy of the Phyllopods, we 

 have two sets of considerations to guide us. First the embryology, 

 anatomy, affinities, and systematic position of the group, and second 



