PKOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 117 



order to supi^ly more definite iuforinatiou as to the so-called boundary 

 line separating the Northern and Southern New England fauna^. 



Rock exposures are entirely wanting about the outer extremity of 

 Cape Cod, and the sandy areas which compose the most of that region 

 are generally of so pure a character as to offer little inducement to 

 animal life in the way of food. The littoral fauna of Provincetown and 

 vicinity is therefore less rich in species than a more diverse region would 

 be. NcA'crtheless a more diligent search than has hitherto been insti- 

 tuted would undoubtedly result in the finding of many species additional 

 to those given below. Prof. H. E. Webster, who spent the entire sum- 

 mer of 1879 in collecting and studying especially the shore annelids 

 about Provincetown, obtained many new forms not included in this list. 



The localities examined in 1879 were about as follows: The inner 

 beach of the cape in front of the town of Provincetown, from the dike on 

 the south to Wood End on the north and from high-water to low- water 

 mark, including the eel-grass areas lying directly off the beach and the 

 broad sand-flats in front of and behind it; the inner beach at Long 

 Point; the piles of the wharves, especially those at the ends of the long 

 steamboat and railroad wharves ; and the outer beaches at Wood End, 

 Eace Point, &c. A few interesting species obtained at Wellfleet by 

 Professor Webster are included in the list, and I am also indebted 

 to him for material from about Provincetown. The identifications of 

 species are only partly mine. Prof. A. E. Verrill furnishes the lists of 

 worms and Nudibranchs; Prof. S. I. Smith has kindly identified the 

 Amphipods and more difficult Decapods; and Mr. Sanderson Smith 

 the more critical species of MoUusks. Mr. O. Harger has also examined 

 the Isopods. In addition to the species contained in the list, a species 

 of Chironomus in the larval stage was found abundantly on the shore, 

 and one or more species of mites were common among Hydroids. Of 

 the one hundred and fifty-seven species included in the list, all but 

 twenty-one were previously known to range both to the north and south 

 of Cape Cod. Of the species whose range has been extended, thirteen 

 belong properly to the fauna of Southern New England and seven to 

 that of Northern New England. The southern species are as follows: 

 Pallene empusa, Pinnixa chcctopterana, Gehia affinis, Mcera levis, Micro- 

 deutopus grandimafius, Amphithoe longimana^ Chelura terebrans^ Gaprella 

 geometrica, Leptochelia algicola, Sigalion arenicola, Stlienelais picta, Antho- 

 stoma rohustum, and Leptosynapta roseola. The northern species are: 

 Leptoclielia cacca^ Praxilla sonalis, Tctrastenima vermiculusy Planocera 

 elliptica, Emhletonia fuscata, Btiliger fuscata, and IJdicardsia sulcata. 

 The only new littoral species discovered by the Commission, so far as 

 the collections have been worked up, is Udicardsia pallida. 



Excepting in a few necessary instances the synonymy of the species 

 has been omitted, but references have been given in nearly all cases to 

 American publications in which the synonymy and range of the several 

 species and other information concerning them are discussed. 



New Haven, Conn., April 8, 1880. 



