BIOLOGICAL SURVEY OP WOODS HOLE AND VICINITY. 115 



1903. I9°4- 



754: (few). 754ibis (many spines). 



7S42bis (several spines). 

 7543 (fragment). 7543 bi s (none). 



7545 (numerous living). 7545 bis (fragment of shell and many spines). 



7546 (few living). 754°°is (spines). 



7S47bis (several living and fragments). 



7549 (many living). 7549 bis ( few fragments and spines). 



7550 (fragments). 755 obis ( few spines). 



7551 (few living). 755 lbis i 1 living, several fragments). 



7552 (few). 755 2bis ( few spines). 



7553bis (few spines). 



7554 (1 small dead). 7554 b is (none). 



7555 (numerous). 



7556 (few). 7556bis (many fragments and spines). 



7557 (1 shell). 



7558 (many living). 



7559 ( few living). 



7561 (about 2 bushels). 



7562 (few living). 7562bis (none). 



7563 (many living). 75 6 3 bis (spines and fragments). 



7564 (many living). 7564bis (many spines). 



7566 (many spines). 



7567 (many spines). 



7568 (many spines). 



7569bis (spines). 



Thus in 1903 the presence of living specimens is expressly recorded in 12 out of 

 36 stations at which Arbacia occurred, and it is certain that they were present at many 

 of the other stations, perhaps in all cases where the contrary is not explicitly stated. 

 Such records as "few," "many," or "2 bushels" certainly refer, for the most part, to 

 living specimens. We may state confidently, therefore, that living sea urchins of this 

 species, sometimes in large numbers, were taken at from one-half to two-thirds of the 

 stations in question. In 1904, on the other hand, living specimens (never in large 

 numbers) were recorded from only 3 of the 23 stations at which Arbacia or its remains 

 were taken. In all other cases the records are for spines and fragments." Further- 

 more, this condition was equally manifest during the succeeding season. Stations 7735 

 to 7757 (dredged in 1905) cover practically the same region of the Sound as stations 

 7521 to 7569. At these 23 stations of the later year spines (in one case fragments) are 

 recorded in 12 cases; in not a single case was a living Arbacia taken. Reference to the 

 complete station list for this species shows that throughout the Sound as a whole (sta- 

 tions 7678 to 7783) living specimens of Arbacia were taken but 5 times during the 

 summer of 1905, and that never more than 2 (in four cases a single one) were taken 

 at one time. 6 



" The number of records for spines only would have been somewhat greater, it is true, during the summer of 1903, had the 

 sand, etc., brought up by the dredge, been searched as carefully that year as during subsequent seasons. 



' It is to be noted in the case of Slrongylolrolus, likewise, that a large proportion of the later (1905) records (7678 to 7752) 

 indicate the presence of spines and fragments only, while living specimens alone were noted in 1903. This last circumstance 

 was, however, doubtless due in considerable measure to the fact that the loose spines of the green urchin were overlooked during 

 the first season (see preceding footnote). The absolute number of stations from which living specimens are recorded in 1905 

 (counting as living all those not listed as "fragments" or "spines") was 8, as compared with 10 during the summer of 1903. 

 Moreover, at 4 out of 5 of the "bis" stations (1904) at which this species was taken the records indicate living specimens. 

 Thus it seems unlikely that Slrongylocenlrolus was unfavorably affected during the winter which wrought such havoc with 

 Arbacia. The same may be said of the "sand dollar," Echinarochnius. We find no evidence of any destruction of this species 

 at that time. 



