612 Appendix to Part II. 



in the same sort of rock, namely, a very hard and very dark olive 

 green sandstone, with the following species. The difficulty of 

 detaching the stone from the shells has prevented me from ascer- 

 taining with certainty whether or not there be an umbilical 

 callus. 



Chiloe, eastern coast. 



Natica steioiata. — PL III. fig. 39. 



Nutica testa depressiusciilo-suhglobosd, crassiiisculd, glabra, anfrao 

 tibus quatuor ad quinque, ultimo maxima, spiraliter substriato. 

 striis subdistantibus ; callo wnbilicali magna, umbilicum om- 

 ninb obtegente, ad labium internum incrassatum antice con- 



jicacto. 



This species resembles Swainson's Natica melastoma in general 

 form, as well as in the umbilical callus : it is however rather more 

 circular and the umbilical callus is rounder. Judging from the 

 apparent general form, I at first sight, when I only saw the upper 

 surface, had taken it for Sigaretus concavus, which it also resembles ; 

 and I was not undeceived until by clearing away the stone I dis- 

 covered the umbilical callus. There are two specimens of this 

 species. 



Chiloe, eastern coast. 



Natica solida. — PI. III. figs. 40, 41. 



Natica testa subglobosd, crassd, Icevi, spird brevi, anfractibus quin- 

 qiu\ suturd subinconspicud, aperturd ovali, labio columellari 

 postice rraftistimo, umbilico mediocri, callo parvo : long. J'8 ; lat. 



1-5, poll. 



This most nearly resembles a very common recent species, 

 which has generally been confounded with N. mamilla, but which 

 I have lately received from D'Orbigny under the name of N. Tiber 

 of Valenciennes, it may be distinguished from that species by being 

 almost destitute of the umbilical callosity. The only specimen is 

 verv much worn, particularly about the spire, so that the true 

 character of the suture is only discernible in one part, and the 

 general appearance of the specimens conveys the deceptive notion 

 of a deep and broad channelled suture. 



Several specimens of a Xatica, closely resembling, but possibly 

 distinct from this species, were procured at Santa Cruz ; they are 

 in a much disguised state, and only a small portion of the shell 

 itself remains, particularly of the outer coats about the suture, 

 which consequently appears very deep and distinct, whereas when 



