1894. PROCEEDINGS OF THE NATIONAL MUSEUM. 181 



oDly, with a nearly vsmooth area below. Otherwise sculptured with ten 

 or more sharp, revolving strife; the varying- prominence of the longi 

 tudinal and transverse sculi)ture, combined with variableness in form — 

 some shells being robust or "chunky," others elongated — produces, as 

 njay be supposed, many varieties. A dwarfed form is often met with. 

 A variety occasionally noticed resembles one aspect of the (iulf of 

 Mexico Nassd rihex; specimens of these occur at La Paz. 



In the more northerly examples from San Diego and thereabout the 

 longitudinal and transverse sculpture is less variable, being more nearly 

 equal in prominence; the shells are darker colored, with usually a con- 

 spicuous dark spot over the mouth. Some of the San Diego specimens 

 closely resemble certain occasional individuals of Nassa lirata Dkr., 

 from Japan. In an interesting paper by F. P. Marat (May, 1870), ''On 

 the variation of sculpture exhibited in the shells of the Genus ISTassa," 

 the author lemarks : 



N. tegula (Reevt; pi. 15, tig. 99, a and h), is simply coronated at the sutures, but 

 when the ribs are completed it becomes the N. coronala, ./. Ad. Some of my varie- 

 ties are only half ril>bed. and others are scarcely ribbed beyond the tubercles. 



NASSA COUrULENTA, C. B. Adams. 



Several spiM-imens. Tres Marias (JSTo. 4()()()(;, IJ. S. N. M.). A ratlier 

 rare shell. 



NASSA LUTEOSTOMA, liroderip and Sowerl>y. 



Several examples. 



La Paz; St. Josef Island; Los Animas P>ay (No. 4()()08, U. S. N. M.); 

 Francisqnita Bay; Angeles Bay; Boca de los Piedras; Tres Marias. 



NASSA f'OMPT.ANATA, P o w i s. 



= N. scabriuscula, C B. Adams. 

 Numerous (Nos. 4G644, 46046, U. S. N. ]\I.). Los Animas Bay ; Mnlege 

 Bay. 



NASSA COMPLANATA; var. MAJOR, S t e a r n s. 



Abundant (No. 75155, U. S. N. M.). Los Animas Bay. 



The above is a much larger form than the average of typical com- 

 planata and much coarser in sculpture, and some of the examples are as 

 large as small specimens of tegula; it suggests on a casual glance N. 

 vibex, of Floridan waters. 



NASSA BRUNNEOSTOMA, Stearns. 



Nasm hrunneoHtoma, Stearxs, Nautilus, May, 1893; Proc. U. S. Nat. Museum, Vol. 

 XVI, 1893, pp. 344, 345. 



Abundant. 



Gulf of California near the mouth of the Colorado River (No. 37239, 

 U. S. N. M.); Guaymas (Nos. 23721, 55951, U. S. N. M.). 



