BALCH: LIST OF MARINE MOLLUSCA. 
141 
and Prime (’TO), p. 395, is abundant in deeper water where it out 
numbers either of the preceding. 
Catulidae. 
Crepidula convexa Say. Smith and Prime (’TO), p. 392. Ver- 
rill (’T3), p. 650. S. 
Common, but less so than the two succeeding species, and appar¬ 
ently seeks deeper water. Eggs still in the two-cell stage up to 
August 20. 
Crepidula fornicata (Lam.). Smith and Prime (’TO), p. 392. 
Verrill (’T3), p. 649. S. 
Abundant at and below low water on Limulus, Fulgur, etc. 
Eggs abundant in July and some still in 2-cell stage on August 23. 
Crepidula plana Say. Verrill (’T3), p. 650. C. ungitiformis 
Lam. Smith and Prime (’TO), p.392. S. 
Abundant on and in other shells, especially Fulgur earica and F. 
canaliculata. 
LlTTOEmiDAE. 
% 
Littorina littoreci (Linn6). 1ST. 
Still a recent arrival (having reached New Haven only in 1880), 
and does not appear as yet seriously to threaten Fossa obsoleta , the 
native competitor for the mud flats. Far less abundant than L. 
palliata or X. rudis , from which it differs considerably in station, 
it is yet common on the edges of marsh and mud flat, and every¬ 
where scattered sparsely among the AT obsoleta. It is not the 
clean dark shell of Massachusetts Bay, but dingy gray and green 
with vegetable growths like AT obsoleta , and appears to average 
larger than north of Cape Cod ; the body-whorl seems more inflated, 
the suture less well marked. Bumpus’s (’98) studies on the ven- 
tricosity of this species seem to confirm such a tendency in southern 
localities. 
Littorina palliata (Say). Verrill (’T3), p. 652. L. littoralis 
var. peconica Smith. Smith and Prime (’70), p. 393. N. 
Abundant on sea walls, piles, and wherever Fucus will grow. 
As variable here as elsewhere. 
Littorina rudis (Maton). Smith and Prime (’70), p. 392. Verrill 
(’73) , p. 651. N. 
