CHAP. XIX. 



CRUSTACEA. 



361 



Crustacea. — References to the few species which were met 

 with in Ecuador will be found at pp. 121 - 127 of the Supplementary 

 Appendix. The Am- 

 phipod {Hyalella iner- 

 7nis, S. I. Smith) to 

 Avhich I was introduced 

 at Machachi [see p. 118] 

 was subsequently taken 

 in pools round about 

 the Hacienda of Anti- 

 sana (13,300 feet), and 

 no Amphipod appears 

 to have been obtained 

 hitherto elsewhere at hyalella inermis, s. i. smith (9800-13,300 feet). 



so considerable an ele- 

 vation. The annexed Figure is magnified ten diameters. 



In the Tables upon pp. 362, 363, a first attempt is made to 

 shew at a glaiUce the highest points which are attained in Ecuador 

 by various forms of animal life. They include two ' stragglers,' 

 namely, the small Bug that has been referred to the genus Emesa 

 [p. 134], which was captured on the sonfhern side of Illiniza, on 

 snow at 16,500 feet ; and a Fly, that Baron Osten Sacken identifies 

 as belonging to the genus Tanyjms, which was taken, on snow, at 

 16,200 feet on the northern side of the same mountain. These 

 insects, doubtless, had been carried by wind away from their usual 

 haunts. The situations where they were found could not have 

 been their natural dwelling-places. 



While forming these collections I was led to remark the fre- 

 quency with which closely similar forms recurred at similar altitudes, 

 upon mountains often long distances apart. This w^as observed in 

 regard to things living in the soil, as well as in respect to winged 

 insects of roving habits. It was not unusual to see Butterflies, 

 apparently of the same species, at closely similar altitudes upon 



widely separated mountains. This was the case with a Lyccena 



3 A 



