38 
BULLETIN OF THE LABORATORIES 
Modiola. The surface is marked by few indistinct concentric lines. 
Genus Aviculopinna, Meek. ■ ■ 
“ Very elongated siibtrigonal, equi-valve, with slightly indicated 
sub-terminal beaks, the shell being, produced in front of them, gaping 
posteriorly ; hinge line very long, edentulous. ” 
1. AviGiilopinna amsricana, Meek. 
(Plate I, Fig. 20. ) 
Our fragmentary specimen is insufficient to warrant a description, 
but is obviously a member of the old genus Pinna. In size and ascer- 
tainable characters it seems to correspond with the species quoted 
above. We are unable to discover that the beaks are not anterior, but 
this may be due to the imperfect condition of the fossil. The charac- 
ter of the ligament grooves is well shown in this specimen. The only 
tangible' distinction between Pinna and Aviculopinna being the posi- 
tion of the umbo, the generic reference is but provisional. 
Solen? sp? 
(Plate I, Fig. 19.)' 
We have figured a fragment which seems to indicate a Rasor shell 
about as completed in outline in the drawing. The piece is too small 
to characterize, but attention is called to it to stimulate collectors to 
examine the rocks for more complete specimens. 
Eclmoridia icf. aspinwallensis, Meek ) 
(Plate IV, Fig. 4,; Plate III, Fig. 17.) 
We have a considerable number of specimens of various sizes, 
but all of the larger individuals are imperfect, while the smaller ones 
•differ considerably from the species quoted. The shell is covered with 
strong concentric folds and very numerous striations. The posterior 
margin is broadly and evenly rounded (sub-truncate in the larger ones); 
the beaks are not prominent ; the lower outline is a regular curve ; 
the anterior margin seems much shorter than in types of E. aspinwall- 
ensis; the. convexity is greatest in front and above the middle and 
there is sometimes a posterior umbonal ridge, nearly reaching the mar- 
