XII. ^Additions to the Marine Mollusca of the Bermudas. 

 By a. E. Yerrill and Katherine J. Bush. 



The additions to the fauna recorded in this article are mostly 

 from the collection made at the Bermudas in April and May, 1898, 

 by the Yale scientific party under Professor Yerrill.* They are all 

 shallow-water (less than 8 fathoms) and littoral forms, no dredging 

 having been done outside the reefs. The new species are nearly all 

 of small size and were mostly obtained by picking over the samples 

 of white shell-sand dredged up from the bottom in 3 to 7 fathoms in 

 Bailey Bay, Murray Anchorage, Harrington Sound, and Castle 

 Harbor. A large part of the bottom of these and the other bodies 

 of water enclosed by the outer reefs is covered with this shell-sand, 

 which varies considerably in coarseness and in the nature of the 

 contained organisms. In general it contains only a very small 

 amount of fragments of corals (chiefly Millepora and Oculina)y 

 some bryozoa, more or less fragments of calcareous algae and echin- 

 oderms, and a number of rather large foraminifera of several 

 species. f But the bulk of the material consists of the broken shells 

 of small mollusca, especially of bivalves of many species. Usually 

 from 80 to 90 per cent, of the bulk of the sand is of this nature in 

 the localities dredged. By washing such sands and sifting them 

 into various grades of fineness it is easy to find a large number of 



* The other members of the party were Messrs. M. C. Cook, W. E. Porter, and 

 C. S. Verrill, all students in the Sheffield Scientific School of Yale University. 

 All the species here recorded, unless otherwise stated, were collected by this 

 party. 



f The following species of Foraminifera, selected from these shell-sands, have 

 been identified by Miss K. J. Bush by comparison with the figures in Dr. Flint's 

 report on the "Eecent Foraminifera " (Report U. S. National Museum for 1897, 

 1899). 



Biloculina bulboides d'Orbigny, Miliolina venusta Karrer, Miliolina circularis 

 Bornemann, Orbitolites niarginalis Lam., with the very abundant Orbiculina 

 adunca Fitchtel and Moll., which was also found by the Challenger party, and 

 Oi'bulina universa d'Orbigny. 



A single specimen was also found of an interesting form of Peneroplis belong- 

 ing to the gi'oup having narrow, comjiressed forms, of which PenerojiUs arieUnus 

 Botch is the type (Challenger Report, p. 304, pi. xiii, figs. 18, 19, 22). It differs 

 in having a more flaring or tapered form and moi'e numerous segments than 

 any species hitherto described. 



