95 



middle, abruptly curved towards the -ide-. and rc-ularly arched from tin- beak- ti tin- front. 

 Beak extended beyond th;it of the dorsal valve and much incurved. l>..r-al valve nearh riat 

 or slightly convex above, with a wide iimb'tim-d -inu-. which often extend- in t'nint aen>-- tin- 

 entire width of the -hjl. Surface -uiooth, or with oli-'-ur- eoiR-,-ntri<- lino ,.f _!-., wth ; .-hell- 

 structure finely punctate. 



Length from two to four or five line-, the width l.ein- e.jual to the length ( ,r a little 

 less. 



Detached valves of ('. <jl -are of not uncommon oceiim-nee in tin- t 'orniferou- 



Limestone. Occasionally individual example- are found h aviriir a length of from >ix to .i_dit 

 lines, and these M i. l!illiii'_ r - think- may perhap- he di-tim-t. I am inciin.-d to think. howe\.r. 

 that they are only lar_e and tumid -peeimcn.- of ' 



/ utt'l l-'<<rin<i(ln. Corniferous Limestone of Port Colborne. 



11G. CKNTKONKM.A HFJATF. (Hillin. 



,(i-u,,,U<i II ilJilii _- madian Journal, New Series, V..i. \'I.. p. 272, ! 



Shell -mall, " elongate, oval, or Bub-rhomboidal ; apical anide from }." to r,n ; -i,l, .., ,. 

 what straight from the beak t" about the middle, where. makiir_ r a rounded aii'jle. they e.<n- 

 _e towards the front margin, which is somewhat truncate fur about one third the width. 

 Ventral valve -Inm-ly but broadly carinate i'rom the ! ak aloiiLT the middle to the front 

 descending with a fht or gently OOnvex slope tn the -idc> ; in outline onlv. L'entlv arch, d h'liL'i- 

 tudinally ; in some specimens nearly straight : the beak -mall, cluii-ated. erect and with a trian- 

 gular iorainen. Dorxil valve -ently convex in the upper half, and with a wide -hallow -inu- in 

 the lower half. Surface smooth. Length I'rom two to four lines ; width ab.mt three tiuirt li- 

 the h-iiL'th" i l!illin_- 



Our collections comprise a few specimens which appear t" in their o- t -ntial eh i- 



racters with the above de.-criptioiv- ; but the materials at pre-ent in my hand- are -in 

 .-uflBcient for identification. 



Locality and Formation. Corniferou.- Lime-tone, port ('nib., rue. 



CIIAITKU IV. 



POLY7.0A nl Till. < uKMKKK'O- - AM" HAMK.TuN I ( i|{ \I AT H . N -. 



The remain- of in the Devonian l;..ck- <>| \\.-ieni (Intario ar.' vi-rv abundant. 



and they are of unii-ual int.-r>--t in many way-. Unfortunately, however, (lev are. (or the 

 mo-! p-irt. more or lo- fragmentary, and their -iu.|\ i- thu- atten-led with -[.eeial diflicult\. 

 -ince there i- no da-- of organisms re^uiiin- greater .-kill and patience in their interpretation. 

 Alto-, (her. 1 have I ..... n able to identify nineteen -peeie- of P ,,)' which no le-- than 



fifteen tO be new. wlii! il foTIDfi lia\e oome to lijht beloiuin- apparently to 



generic t\pe- 'I'bere remain-. ho\\ever, a con-iderable number of 1'nnn-, of wbieli th. 

 terials at pre-ent in my hand- are too fra'_'iie-ntar\ to jii-tifv me in de-.-iibinir them delinii 

 The forms which I have emi-blered my-el!' warranted In describing, belong to the folio? 



: two -| oi - . /' . fbui 



(one -]" <'> (one ~\ iopora 'two -j,, -ej, - - | (one B] 



/;. i : w a "ic - ' .in,- species), and / 



; typical numb, r- of tin- family of the / 



and they coinpri-e more th-n half of the total number ot | , , : - i.lmt iti, ,1. It j- (,, tl 

 three _.. Her 'hyt nio-t ,.f the undd. rminable fra-ment- belmi^ . -o that ihe / 



m u -t be con-pi. T. d a- b a\ in-_' had it ,b\ .-lopm, -nt in the I >> \uiiian period in Nnrth 



\iin-rii-a. The u'.-iier i ' I ' now charai-t, ri-ed |',.r I b, (ir-t lime, :d-n 



bel.,[|._' to the /. '.'',,/,;, |||oU'_'ll t bey e.\ ll i I li t IIian\ . \ I I 'a, .I'd i 1 1 a r\. and indeed, alt 



unprecedented, point- of Mrm-tup-. 'I'b, n. ean bardlv be c. ,in| :ir , ,1 



with any known -mup of the I 1 ., . : i,- / I. -it ih. w.-ll known Silurian genua /' ' 



i- represented by at lea-tone form ; und ' . . it. d to ,-, n.iin 



well-known type- in both the Silurian and the ( 'arb.iniler.'U- 



