- c\-^o - 



J± 



t"re, its :=;'h-r-'r anr"' hr _. -i-n--- '^-r ■'' ->rr.--'l -rf-r^^ its less 



elevate"^ 'beaks, ito sj ' ' " ,■ Si:3al].er and more dlsoinctlj liniit- 

 efi anterior dorsal area, and its more nearly cin- ;line. 



It. £8, lOii. , '. ... 'T' rnrn. The lar--"sf: r-r^r^-' 'bserve-'' 



has a length of 42 anl a diameter of '35 uuu. , Vvliil pecirrien of 



_?• enns '"Ivani ous of the sarae size has a diameter of onlj? ^5 mm." 



.\ J cardinal "'.__:.. -^^ -f^he fossil are ■-'"'r- r^^ie'r^ r-.i^ve -^i^-'^r- 

 out than in the recent shell, in which t>:e tv.o a mall ex" cardinal 

 teeth are ns-ually very ohscure or even ohsolete Xla. adult speoi- 

 •ens." (Dall, 190.?) 



~:;ve locality .- 30Y;den, Jamaica. 



Shell of moderate sizu, outline nearly circular; immature 

 v-''.ves strongly ".T.nrrt-- oo-,- •-! .-, shell thiolrenc^, v--.oessively con- 

 vex and suhspherical; omhones of adult shells relatively broad 

 and low, on ;o "" liigh'-r and narmwer; posterior area 



"broad; \7el1-def inf^'" , :■■.+■ ^---^v rSorsar- - ' ■ ''- "broad; ex- 



ternal surface sculptured with regular, closely-spaced concen- 

 tric rugae, continuous across the posterior bh ' -r areas 

 and on the largest shells crowded tovrar-'"' -'■ L.tr^.l . argin; 

 hinge strong; inner margin of the valve often "bearing obscure, 

 minut e ere nula t i o ns . 



j^ema rlrs . - Althou-"!^ -^^-;o specie: ' '- represented "by a lt'-'^~° 

 num"ber of individn.als, there is a rather ' - the ser- 



ies "between the few excessively convex, largest forms end. the 



