184 MAZATLAN UNIVALVES 



Ordinary state. — Tablet 851 contains 3 sp. liglit brown. — 

 852, 4 do. darker. — 853, 4 do. whitish margin.— 854, 4 do. broad 

 white margin. — ^855, 4 sp. blackish brown, white margin. — 856, 

 4 do. penciled.— 857, 4 do. tesseUated.— 858, 4 do. nearly black. 



Specimetis shewing exterior. — 859, 3 sp. fine growth, with 

 epidermis.— 860, 4 do. principal ribs few. — 861, 5 do. more 

 numerous. — 862, 5 do. principal ribs scarcely developed. — 863, 

 1 do. with verj- fine crowded riblets, here and there developing 

 into principal ribs. — 864, 2 sp. very conical. 



Tablet 865 contains 4 sp. probably belonging to this species, 

 but approaching S. a;quilirata. Principal ribs scarcely traceable. 



240. SiPHONAEIA ^QTTILIEATA, 71. S. 



S. t. suhconicd, ovali, regulari, liris numerosis .siibrugulosis, 

 mqualihus, radiatim ornatd, interstitiis haud latis, Icevibus ; 

 fusco-olivaced, liris altis ; epidermide tenui, adhcBvente ; pagind 

 interna fused, mx iridescente ; margine crenulato ; canali sub- 

 centrali, extus haud prominente. 



One specimen of beautiful growth in the Mazatlan collection 

 agi'ees with a larger but somewhat irregular one in that of 

 Mr. Cuming, in characters which appear to separate it from 

 all varieties of S. Lecanium. Riblets equal, interstices smooth, 

 channel nearer the middle and not conspicuous either by 

 sweUing or special marking outside. The Mazatlan specimen 

 has much broader interstices than that of Mr. Cuming ; but as 

 the riblets are bifurcating, it is probably not fully grown. 

 There is no trace of striulaj. The examination of more speci- 

 mens may possibly merge it into the poh-morphous S. Lecanium, 

 from the extreme varietj' of which the non-prominence of the 

 oanal appears to separate it. Mr. Cuming's specimen measures 

 long. '83, lat. '57, alt. "3. 



Jfab. — Gulf of California, Lieut. Shipley. — Mazatlan; 1 sp. 

 only ; L'pool Col. 



Tablet 866 contains the specimen. 



241. SiPiroNAEiA sp. ind. 



Tablet 867 contains a very young specimen, "07 by "05, of 

 Navicella sha])e, with a large spiral apex, extremelj- thin, and 

 evidently belonging to a very much larger species than S. 

 Lecanium, possibly to S. gigas. 

 Hah. — Mazatlan ; 1 sp. in shell washings ; L'pool Col. 



