180 SHELLS OF LOWER CALIFORNIA—STEABNS. vol. xvii. 



which the entire surface was broadly and deeply channeled or grooved, 

 agreeing perfectly with specimens in the National collection (60074) 

 which measure 2.9 inches in length by 1.92 inch in width; from this size 

 younger examples as small as 1 inch in length by .0.58 inch in width 

 (the outer lip thin at this age), show the same characters. In KeUettii 

 (00076) Hinds' form, the shell exhibits only three of these channels, 

 near the base of the body whorl. Mr. Fisher's specimens prove that 

 the grooving is an uncertain character. The number of individuals col- 

 lected by him was fortunately ample enough to settle all doubts and 

 prove that the two forms as above should be united under one specific 

 name; as Mr. Eeeve's appears to be thetirst in order of time, it must be 

 adopted. The National Museum series exhibits all of the intermediate 

 forms or varieties; the connecting links (60075) were received not only 

 with the Fisher shells but from Hemphill and other sources. 



The shells of the foregoing when living or fresh are covered with a 

 thick blackish epidermis, which is apt to peel or flake off when very 

 dry. The epidermis has the same character in the rare Mitra BelcJieri, 

 in common witb other West American related forms, and we may pre- 

 sume it lives in similar muddy stations. 



Examples of M. ^l^thiops of the form that is grooved throughout 

 have been collected at Cerros or Cedros Island, on the ocean side of 

 Lower California; it was collected years ago by Capt. Scammon, in 

 Scammon's lagoon. The late Prof^ W. M. Gabb found it at San Juanico, 

 on the ocean side of the peninsula, in 1867, and Henry Hemphill has 

 contributed specimens to the National Museum, collected by him at San 

 Ignacio lagoon (No. 105432, U. S. N. M.); Manuel lagoon (No. 105433, 

 U. S. N. M.) ; Point Abreogos " around rocks" (No. 105434, U. S. N. M.) 

 also at Scammon's lagoon (No. 105428, U. S. N. M.). Ballenas Bay (No. 

 102256, U. S. N. M.), U. S. Fish Commission, Albatross. 



Family Nassid^. 

 NASSA TEGULA, Reeve. 

 ^N. tiarida, Kiener. 



Abundant. 



La Paz; Mulege Bay (No. 46016, U. S. N. M.). Los Animas Bay 

 (No. 46615, IT. S. N. M.); Loreto. This variable species is exceedingly 

 numerous at many places in the Gulf region and elsewhere on the shores 

 of Lower California; it exhibits many interesting and suggestive varie- 

 ties. The usual Gulf form is of a pale, dingy yellow or yellowish- 

 white color, in some specimens running into an ashen-blue on the last 

 half of the final whorl, with sometimes two, more rarely, three dark 

 color bands, the upper one interrupted by the sculpture, which latter 

 consists of 8 or 9 strong longitudinal ribs, interrupted and broken into 

 nodules by a transverse groove, Just below the suture ; the ribs evanesce 

 on the last third of the basal whorl, showing three or four strong nodules 



