BALCH: LIST OF MARINE MOLLUSCA. 
139 
era ” or unassignable, but the striking correspondence between the 
figures for gasteropods and pelecypods and between the results for 
Coldspring and N ew Haven (results obtained at first by independ¬ 
ent classings of the species which were only afterwards compared) 
shows, I repeat, that they represent real facts. The comparison 
between Coldsjwing and New Haven at least is just. 
The upshot is, as before, that two pretty distinct faunas in this 
region overlap, the more southern one contributing a quota rather 
more than twice that of the more northern one; and further, the 
increase in the prejmnderance of southern forms can be detected 
in a range of forty miles. > 
In the list which follows the nomenclature adopted is that of 
Hall (’86, ’89, ’89) wherever possible, while in one instance I have 
followed Apgar (’91). The arrangement of the gasteropods is 
that of Fischer (’87), excepting the nudibranchs where I have 
followed Bergh (’92), and that of the pelecypods is that of Pel- 
seneer (’94, ’97). The only synonymy attempted in most cases is 
Verrill’s names in his report (’73) and Smith and Prime’s names in 
their report (’70), given for the sake of convenience in comparison. 
I have adoj)ted the scale of “very abundant” “abundant” 
“ very common ” “ common ” “ tolerably common ” “ rather uncom¬ 
mon ” “ uncommon ” “ rare ” and “ very rare ” as the best available 
way of describing the present condition of the molluscan population. 
Too vague to serve as an absolute measure it is yet to be hoped 
that it will prove accurate enough in relative terms to enable some 
future student to determine what changes in distribution and 
adjustment of equilibrium a given number of years may have made 
in the so-called “permanent residents” of a given locality. If it 
could be supplemented by a series of quantitative determinations 
of the actually prevailing “ mode ” in a series of the local forms it 
might prove a useful reference-point for future comparison. 
A capital N or S following the synonymy will indicate that the 
corresponding species was counted as “Northern ” or “Southern.” 
CEPHALOPODA. 
Loliginidae. 
Loligo pealii Les. Smith and Prime (’70), p. 405. Yerrill 
(73), p.635. N. 
One was taken in August, 1899, and specimens from the harbor 
