THE NAUTILUS. De 
cases they are slightly broken. In some of the Indian and African 
forms this sculpture becomes irregularly rayed and zig-zagged; in 
the European forms it becomes somewhat concentric and often 
broken, while in Lampsilis we have the farthest departure from the 
simply radial, that is, the rays are all looped and joined in the cen- 
ter, where they are drawn up towards the beak. This genus has 
without doubt the most highly developed animal of any of the 
Unios, and is, in all probability, the most modern. I have seen no 
extinct forms which certainly belong to it, and it was probably 
developed in North American waters, to which it is still confined. 
ISAAC LEA DEPARTMENT. 
‘ 
[Conducted in the interest of the Isaac Lea Conchological Chapter of the Agassiz Associa- 
tion by its General Secretary, Mrs. M. Burton Williamson. ] 
COLLECTING IN MONTEREY BAY. 
(Extract from the report of Mrs. E. H. King. From the Transactions of the Isaac 
Lea Chapter for 1896.) 
In the month of September I spent two weeks at Monterey Bay, 
and collected shells on about three miles of shore-line, rocky head- 
lands and sandy beaches. Along the shore I found many patches of 
soil literally packed with fossil shells. In the black soil they are 
soft and crumple easily, but in the sand hills near the light house 
they are quite firm. Haliotis rufescens Swains, is the most abundant, 
but there are also great numbers of H. cracherodii Leach, and a 
variety of limpets; also Chlorostoma funebrale A. Ad. I found in 
the sand hills a large perfect shell of Purpura canaliculata Duclos, 
much larger than any of the live shells I have seen. 
We go down on the rocks as the tide goes out, take our lunch with 
us, and work until the tide rises and compels us to return. The 
first shells we find are the Littorinas, so very plentiful that large 
spaces and crevices are full of them. Two species abound L. plan- 
axis and L. scutulata. There also the limpet appears, Acmca spec- 
trum is the highest, but is also found low down, and larger near low 
water. Next were Acmea patina Esch., and A. scabra Nutt., then 
appears A. persona and A. pelta Esch. Lottia gigantea Gray, is very 
near low water mark, and a few large specimens of nearly all the 
others, the lower on the rocks they were the larger were their thin 
shells. Here also I found a few shells of Gadinia reticulata Sby. 
