CONTENTS. 



Page 

 No. 1. — Report on the Results of Dredging by the United States Coast 

 Survey Steamer " Blake." XXX. Report on the Holothurioidea. By 

 Hjalmar Thekl. (1 Plate.) October, 1886 1 



No. 2. — A Second Supplement to the Fifth Volume of the Terrestrial Air- 

 breathing Mollusks of the United States and adjacent Territories. By 

 W. G. BiNNET. (3 Plates.) December, 1886 23 



No. 3. — Simple Eyes in Arthropods. By E. L. Mark. (5 Plates.) 

 February, 1887 49 



No. 4. — Studies from the Newport Marine Laboratory. XVllI. On the 

 Development of the Calcareous Plates of Amphiura. By J. W. Fewkes. 

 (3 Plates.) May, 1887 107 



No. 5. — Preliminary Account of the Fossil Mammals from the White River 

 Formation contained in the Museum of Comparative Zoology. By W. B. 

 Scott and H. F. Osborx. (2 Plates.) September, 1887 151 



No. 6. — The Eyes in Scorpions. By G. H. Parker. (4 Plates.) Decem- 

 ber, 1887 173 



No. 7. — Studies from the Newport Marine Laboratory. XIX. On certain 

 Medusae from New England. By J. W. Fewkes. (6 Plates.) February, 

 1888 209 



No. 8. — On certain Vacuities or Deficiencies in the Crania of Mammals. 

 By D*. D. Slade. (2 Plates.) March, 1888 241 



No. 9. — The Superior Incisors and Canine Teeth of Sheep. By Florence 

 Mayo. (2 Plates.) June, 1888 247 



No. 10. — The Rattle of the Rattlesnake. By S. Gauman. (2 Plates.) 

 August, 1888 259 



