1897.] NEW YORK ACADEMY OF SCIENCES. 159 



ter. Crawling among the cominon barnacles, Balanus halan- 

 oides (?), is a rather small greenish Nereis. 



The Isopod Limnoria tenehrans causes enormous damage to 

 the wharf piles. Teredo is entirely unable to compete with this 

 very small crustacean in the amount of ruin wrought. Another 

 pest of commerce, Balanus tintinnabulum (?) is so effective in 

 covering the keels of ships, plying between Puget Sound and 

 the Orient, that the bottoms must be scraped after every four 

 voyages. This barnacle is probably taken in more southern 

 waters (Darwin). 



Part II. Fauna from Depths of from Five to Thirty 

 Fathoms About Port Townsend. 



Since comparatively little material was procured from muddy 

 bottoms, it will be understood that unless otherwise stated, the 

 following forms inhabited sandy or rockj^ bottoms. The locali- 

 ties will be discussed in the same order as in the foregoing part, 

 notes of general interest being appended to the locality in which 

 the forms concerned were found. 



Seqiiim Bay. 



On account of the unfavorable nature of the bottom of Sequim 

 Ba}^ but little variety was shown in the extensive dredging 

 carried on there. . 



The Gastropods, Pteronotus and Lunatia occur in great num- 

 bers. Their vacated shells are used by great numbers of com- 

 mensal forms, the principal tenant being the hermit-crab Eupa- 

 gurus alaskensis. The smaller individuals inhabit any shells 

 which they find convenient, but when a length of six inches is 

 attained, Lunatia shells seem to be preferred. They are notice- 

 able for the prominent red and white striped thoracic feet and 

 antennae. Along with the hermit-crab, these moUusk shells har- 

 bor a commensal Nereis of undescribed species, which is inter- 

 esting for having assumed the colors of the crab for possessing 

 degenerate posterior region of the body and for the habit of pro- 

 jecting from the shell just as far as the body is pigmented. In 

 this position, the Nereis very closely resembles one of the tho- 

 racic legs, although when out of water one cannot demonstrate an 

 identity of pattern. The disguise is made more complete by the 

 sj'nchronous movements of the two animals into the shell when 

 surprised. The posterior end of the worm, beside being un- 

 pigmented, tapers very rapidly from the thirtieth somite back- 

 ward. The branchial lobes, however, are well developed 



