THE NAUTILUS. 23 



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. Haliotls rttfescens Swains, is the most abundant, 

 but there are also great numbers of H. cracherodii Leach, and a 

 variety of limpets; also Chlorostoma fimebrale 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, Acmcea spec- 

 trum is the highest, but is also found low down, and larger near low 

 water. Next were Acmcea 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. 



