214 CARNEGIE INSTITUTION OF WASHINGTON. 



The rate of nerve-conduction is probably accelerated by an enzyme (E. N. 

 Harvey, 1911). 



R. S. Lillic, 1910, appeal's to be mistaken in assuming that the rate of 

 nerve-conduction is necessarily dependent upon the electrical conductivity of 

 the solution surrounding the nerve, for the decline in rate of nerve-conduction 

 is practically identical whether we dilute sea-water with 0.415 molecular MgCU 

 or with distilled water — in other words, whether we maintain a constant 

 electrical conductivity or reduce it nearly in the same ratio as the dilution. 

 (Mayer, 1915, Proc. Nat. Acad. Sciences, vol. 1, p. 270.) 



Research upon Bermuda Annelids, by A. L. Treadwell. 



My work for the summer was a continuation of earlier work on a syste- 

 matic study of the Leodicidae. Since my earlier collections had covered rather 

 thoroughly the fauna of the Tortugas, it was decided to extend the observa- 

 tions this year to the Bermudas. To Professor E. L. Mark, Director of the 

 Bermuda Biological Station, and to Dr. W. J. Crozier, Resident Naturalist, 

 I am indebted for permission to work at the station and for many courtesies 

 shown to me while there. Miss Helen Fernald, of Columbia University, 

 rendered very efficient service as artist. 



So far as can be determined on the basis of one season's collecting, the 

 Leodicid fauna of Bermuda differs in no considerable degree from that of the 

 Tortugas. The main differences, as noted below, were in the relative abun- 

 dance of the species, and this may have been nothing more than a seasonal 

 variation. VerrilP and Webster^ have described some species of Leodicidae 

 from Bermuda, and I found only 3 species which have not been already 

 noted from this locality. One is a possible new species of Marphysa, another 

 is Leodice filamentosa of Grube, which I have not seen at the Tortugas, and 

 the third is a new species of Lumhrinereis. 



Leodice longisetis Webster, mentioned by Verrill as one of the commonest 

 species of the large Leodicidse, was found only once — on the lower surface 

 of a flat rock in Tucker's Bay, Harrington Sound. I have examined Web- 

 ster's type of this species on the U. S. National Museum, as well as the 

 specimen which he identified as Leodice (Eunice) violacea. They are certainly 

 of the same species, the type being a very small and probably immature 

 specimen. Leodice (Eunice) violacea maculata of Ehlers is also undoubtedly 

 of this species. Verrill states that this latter is without a white nuchal 

 band, but one in his collection labeled violacea-maculata has this band and is 

 certainly L. longisetis. Apparently violacea has not been collected in Ber- 

 muda, and violacea-maculata is synonymous with longisetis. 



The commonest of the large species of the coral reefs was L. mutilata of 

 Webster, and it occurred also in considerable numbers in porous rocks close 

 to the margins of the islands. Immature forms (differing from the adults 

 in much darker coloration, but recognizable from the colorless tips of the 

 tentacles and cirri and the prominent nuchal band) were also frequent. 

 Apparently the breeding-season of this species is late in the summer, for a 

 few sexually mature males were collected in July. 



Leodice fucata, the "Atlantic palolo," so common in the Tortugas and in 

 Porto Rico, has never been recorded from Bermuda, and none appeared in 

 my collections. For this reason it was not possible to secure additional data 

 concerning the time of swarming. L. cariboea Grube, a large form fairly 

 abundant in the Tortugas, occurred only rarel.y. 



'Verrill. Turbellaria, Nemertina, and Annelida of the Bermudas. Trans. Conn. Acad. Arts 

 and Sci., Nov. 1900. 



'Webster. Annelid.i frrmi Rcrnnidn. Bull. U. S. National Museum, 18S4. 



