120 OXYSTYI.A, MKX ICO, KFC. 



Monat-her. Akad. Wiss. Berlin, 1863, p. .VI '2 ; Malak. Bliitt. xii, p. 

 42 (1865). PKK. Monogr. Ilelic. Vivent. vi, p. ll9 FISCH. & 

 CROSSE, Miss. Scient. Mex., Mollusca, i, p. 447 PILSHKY, Proc. 

 Acad. Nat. Sci., Pliila. IS',11, p. 317. ( hi/nt/icus princeps SxoLL, 

 Guatem. Reisen, p. 430. Ortalichns feriissaci MAKTKNS, Biol. 

 Centr. Amer. p. 184, pi. 10, f. 8-10 (exclusive of South American 

 localities and references). 



Not (>. feriissaci MARTENS, Binnenmoll. Vent 1 /., nor of STREBEL, 

 Beitr. Mex. Land- und Siisswasser-Conchylien, = 0. maracaibensis 

 Pfr. 



"This species is chiefly characterized by the combination of streaks 

 and spiral bands. Some specimens come very near to the young 

 -talc of O. princeps; and others to O. nndata Brug., from the Carib- 

 bean islands and Florida, which, however, is ordinarily more ellipti- 

 cally elongated, and has paler, rather bluish-livid, bands and streaks." 



The description given above is that of Dr. von Martens, and fig- 

 ures 16 and 17 represent the typical specimens figured by him. Figs. 

 14, 1") an- specimens from Salinas Bay, Costa Rica, where it occurs 

 with <>. priiici'jis. Fig. 13 represents a shell from Shkolak, Yucatan. 



In my opinion, the shells from Colombia and Venezuela referred 

 to feriissaci by von Martens and Strebel are forms of O. maracaibenr 

 sis 1'tV., the large series before me practically demonstrating this 

 position. In fact, O. feriissaci belongs to an appreciably different 

 stock, that of O. princeps; agreeing with that species in the smooth- 

 ness of the surface, rarity of black varices (not more than one or two 

 on the whole shell, and those usually remote from the lip-edge), and 

 in contour. It is sometimes a mere matter of opinion whether a 

 given specimen be referred to princeps or io feriissaci. It is perhaps 

 better as a sub-species of princeps than as a distinct species. 



In its retention of spiral bands in the adult, < >. feriissaci shows a 

 more primitive condition of the color pattern than 0. princeps. 



YAK. TKhiM i A (von Martens). PI. 1 8, figs. 4, 5, 6 ; pi. 1 7, fig. 18. 



Form as in f,-riixsnrl or xunewhat more -lender, the aperture less 

 than half the length of the shell ; yellow or brownish below, paler 

 above, with three brown spiral bands, the upper one. often faint, 

 almo>t wauling ; longitudinal streaks typically wanting, but some- 

 time- |,n -i-nt though very taint ; apex blackish ; dark varices few or 

 one. u-ually none on the latter half of the last whorl ; peristome 



