514 Verrill and Bush — Marina Mollusca of the Bermudas. 



minute species of shells, both of gastropods and bivalves. A con- 

 siderable proportion of the small gastropods were living when 

 taken, and a smaller proportion of the bivalves. The bulk of the 

 broken and dead shells have evidently passed through the diges- 

 tive organs of the abundant large holothurians {Sticho2nis), sea- 

 urchins {Toxo2)neustes), many fishes, etc., which swallow great 

 quantities of the organic muds and sands for the sake of the 

 living organisms that they contain. To this cause, in part, is 

 also due the finely comminuted calcareous mud, which is every- 

 where mixed with the coarser materials. 



Some interesting additions to the list of bivalves were obtained 

 by breaking up large masses of dead corals from the reefs. These 

 ^re mostly true borers, but others are nestlers that find shelter in 

 the holes made by the boring species. No doubt there are many 

 more species to be added to the list of the Bermuda fauna whenever 

 careful dredging shall have been made over the large areas of bottom 

 outside the bordering reefs, in 10 to 60 fathoms of water, where the 

 fauna is, as yet, practically^ unknown. It is well-known to the local 

 fishermen that several of the large showy shells like Stromhus gigas, 

 Triton variegatus, etc., are rarely to be found except in rather deep- 

 water on the south side of the islands. Several of the littoral shells, 

 also, are common on the south side, but rare or absent on the north 

 side of the islands. 



The present list does not include the pteropods, the nudibranchs, 

 nor the tectibranchs with rudimentary shells, which will be discussed 

 in the next article. 



Several lists of the marine mollusca of the Bermudas have already 

 been published. \ 



J. Matthew Jones, in 1859,* published one of the earliest lists, 

 and in 1876f added considerably to the number of species. In the 

 latter work 87 species were included, of which 55 were gastropods, 

 31 bivalves, with 1 cephalopod. 



A. Heilprin, in 1889, J enumerated IVI species, of which 110 were 

 gastropods, 51 bivalves, and 4 cephalopods. 



W. H. Dall, in 1889,§ recorded 163 species, of which 105 were 



* Jones, J. Matthew. The Naturalist in Bermuda. London, 1859. 



t The Visitor's Guide to Bermuda, pp. 137-140. Halifax, 1876. 



:j: Heilprin, Angelo. The Bermuda Islands, pp. 166-181, with i^lates 15 and 

 17. 8vo. Philadelphia, 1889. 



§Dall, William Healey. Bulletin of the U. S. National Museum, No. 37. 

 Washington, 1889. 



