SMITH.] ZOOLOGY ^AMPHIPOD CRUSTACEANS. 611 



ably shorter than the basal portion of the outer. Divisions of the tel- 

 son with two or three terminal spines each, and a single spine about 

 the middle of the outer margin. 



Length from front of head to tip of telson, 10™™ to 15™™. 



Wahsatch Mountains, Utah ; L. E. Eicksecker, collector (collection 

 Peabody Academy of Science). 



EXPLANATION OF PLATES. 



Plate I. 



Fig. 1. — Hyalella inermis, female ; lateral view, enlarged 16 diameters. 

 2. — The same, male ; terminal portion of one of the second pair- 



of thoracic legs, SQen from the outside, enlarged 50 

 • diameters. 



3. — Hyalella dentata, adult male ; terminal jjortion of one of the 



second pair of thoracic legs, seen from the outside, 



enlarged 50 diameters. 

 4. — The same, youug male; 3.7™™ long; terminal portion of 



the corresponding leg, enlarged 50 diameters. 

 5. — The same, adult male; maxillipeds, seen from above, enlarged 



80 diameters. The hairs are omitted from the palpus on 



one«side. 

 6. — The same, adult male; one of the first pair of thoracic legs 



with its epimeron, seen from the outside, enlarged 50 



diameters. * 



Plate II. 



Fig. 7. — Gammarus robustus, female ; lateral view, enlarged 5 diam- 

 eters. (The secondary flagellura is figured upon the first 

 instead of the last segment of the peduncle of the anten- 

 nula by a mistake of the engraver.) 

 8. — The same, male ; flagellum of one of the antennae, enlarged 



25 diameters. 

 9. — The same, male ; terminal portion of one of the first pair 

 of thoracic legs, seen from the outside, enlarged 25 diam- 

 eters. 



10. — The same, male ; same portion of one of the second pair of 

 thoracic legs, enlarged 25 diameters. 



11. — The same, female ; terminal portion of one of the first pair 

 of thoracic legs, seen from the outside, enlarged 25 diam- 

 eters. 



12. — The same, female ; same portion of one of the second pair 

 of thoracic legs, enlarged 25 diameters. 



13. — Gammarus Umnceus, male, from lake near Long's Peak; ter- 

 minal portion of one of the first pair of thoracic legs, seen 

 from the outside, enlarged 20 diameters. 



14. — The same, male from the same locality ; same portion of 

 one of the second pair of thoracic legs, enlarged 20 diam- 

 eters. 

 (All the figures drawn by S. I. Smith.) 



