272 
PALEONTOLOGY OF NEW YORK. 
Genus MIMULUS, Barrande. 1879. 
PLATE XIC, FIGS. 23-32. 
1878. /Spirifera (?), Miller and Dyer. Journal Cincinnati Soc. Nat. Hist., vol. i, p. 37, pi. ii, fig-. 3. 
1879. Triplesia, Hall. Trans. Albany Institute, vol. x. Abstract, p. 16. 
1879. Mimulus, Barrande. Systeme Silurien du Centre de la Bohfime, vol. v, p. 109, pi. 1, fig. iii; 
pi. 9, figs, iii, iv, vi. 
1882. Triplesia, Hall. Eleventh Ann. Rept. State Geologist of Indiana, p. 298, pi. xxvii, figs. 19-22. 
1889. Streptis, Beecher and Clarke. Memoirs N.Y. State Museum, vol. i, No. i, p. 30, pi. iii, figs. 9,10. 
The affinities of this peculiar group of fossils have not hitherto been cor¬ 
rectly understood. M. Barrande has given no clue to the interior characters 
of the shells, and as the genus has been recognized only in the Bohemian basin 
it has not been closely studied by other authors.* After a careful comparison 
of M. Barrande’ s figures of the Bohemian species with the fossil known as 
Triplesia puHllus, Hall, or Spirifera Waldronensis, Miller and Dyer, from the Niagara 
fauna of Indiana, there remains little doubt of their being congeneric forms. 
The diagnosis of the genus, given by M. Barrande, is in the following 
terms: 
“ Cette forme exterieure est completement inverse de celle de Spirifer, en ce 
que le bourrelet, bien marque, se trouve sur la valve ventrale, tandisque le sinus 
correspondant se montre sur la valve dorsale. 
“ La charniere est droite, mais n’occupe pas toute la largeur du fossile. L’area 
bien developpee presente sous le crochet une ouverture triangulaire, fermee par 
un deltidium, jusqu’au crochet. Celui-ci parait conserver un petit trou rond, 
que nous observons sur un specimen non figure. 
“ II est rare de pouvoir observer le deltidium, parceque la trace de la soudre 
avec l’area est completement efface. 
“ Les 2 especes typiques, Mim. perversus et Mini, moera , PI. 9, presentent exac- 
tement les caracteres, que nous venons d’exposer.” 
The exterior form of these shells is subtrihedral like Triplecia, and is 
subject to some variation, for of the three species described by M. Barrande, 
two, M. perversus and M. moera, have the strong median fold on the pedicle- 
* Zittel (Handbuch dev Palseontologie, vol. i, p. 684) made it a sub-genus of Spirifer, and (Ehlert 
(Fischer’s Manuel de Conchyliologie ; Bvachiopodes, p. 1313) placed it with doubt under the family Rhyn- 
CHONELLID / E . 
