DISTRIBUTION OF CERTAIN INVERTEBRATES ON A RESTRICTED 

 AREA OF SEA BOTTOM* 



Edna M. Perry, 

 Bellingham, Wash. 



The following table shows the distribution of the common Arthropods, 

 Echinoderms, and Mollusks on the area northeast of Brown Island, shown 

 by oblique rulings on the map on jaage 17 i of the preceding paper.** The 

 distribution as given is for the month of July, 1915, and for the area in 

 question only. The species are arranged according to their uppermost 

 limit. Relative abundance and habitat are indicated by figures and letters : 

 — 1, abundant; 2, common; 3, few; 4, incidental or accidental; r, on rocks; 

 11, under rocks ; *, sand ; I, algae ; m, rock beds. 



Shore 



Lami- 

 narian 



Coralline Subcoralline J 



Depth in Meters 



Scientific Name 



Common Name 



1 10 20 40 55 100 139 146 165 g. 



I.ittorina scutulata Gld. 



j.ittorina sitchana Phil. 



,\^maea persona Esch. 



Acmaea pelta Esch. 



TJemigrapsus nudus Dana 



'L'hais saxicola Val. 



Paphia staminea Conr. 



Thais canaliculata Duel. 



Balanus halanoides L. 



-Mytilus edulis L. 



Acmaea patina Esch. 



Bittium eschrichti Midd. 



Macoma nasuta Conr. 



Leptasterias hexactis St. 



Pisaster ochraceus Br. 



Petrolisthes eriomerus St. 



Lophopanopeus bellus St. 



Cucumaria miniata Br. 



Cardium corbis Mar. 



Marcia Kennereyi Rve. 



Acmaea mitra Esch. 



Chrysodomus dirus Rve. 



Margarites lirulata Cpr. 



Margarites pupilla Gld. 



Fissuridea aspera Esch. 



Calliostoma costatum Mart. 



Crepidula nivea Adams 



Strongylocentrotus drobachiensis Mull 



Snail 

 Snail 

 Limpet 

 Limpet 

 Pvirple shore-crab 

 Snail 

 Clam 

 Snail 

 Barnacle 

 Mussel 

 Limpet 

 Snail 

 Clam 



Six-rayed star 

 Common starfish 

 Plat shore-crab 

 Black-claw crab 

 Cucumber 

 Clam 

 Bivalve 

 Limpet 

 Snail 

 Snail 

 Snail 

 Limpet 

 Snail 



Slipper shell 

 Urchin 



lu 



*Editor's Note — The responsibility for the accuracy of this work is accepted 

 by Dr. V. E. Shelford of the University of Illinois, under whose direction the 

 work was done. Acknowledgments are due Prof. Trevor Kincaid, Miss Bertha 

 Challis, Dr. Nathan Fasten, Mr. H. M. Du Bois and Dr. H. L. Clark (Mus. Comp. 

 Zoology) for assistance in the preparation of the manuscript and reading the 

 proof. 



**Shelford, V. E. Physiological Differences between Marine Animals from 

 Different Depths. Puget Sound Marine Sta. Pub. 1:157-174. 1916. 



(175) 



