5O PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. XXXIV. 
Figs. 1-2 (1225 B1, specimen No. 67-67a), mold of exteriors of 
brachial valve. 
Figs. 5-6 (1225 B1, specimen No. 97-98), mold of exteriors of ped- 
icle valve. 
Fig 9 (517 A7-+, specimen No. 24), exterior surface brachial valve. 
Fig. 10 (517 A7-+, specimen No. 25), exterior surface pedicle valve. 
The specimens marked 1225 are from Villenova, Chautauqua 
County, near the eastern boundary of the town. Specimens marked 
517 AT+ are from a loose slab found in Chautauqua Creek, West- 
ville, Chautauqua County, at about 850 feet A. T. The slab is be- 
heved to come from near the base of the Chemung formation of that 
locality. , 
Comments.—The species Orthis leonensis as defined and figured by 
Hall ¢ covers three forms, namely, form alpha (figs. 3, 7, and 8 of his 
Plate VII1); form beta (figs. 4 and 6) and form gamma (fig. 5). 
The form a/pha, represented by Hall’s figures 3, 7, and 8, is chosen 
as the type of the species Orthis leonensis as here restricted. No 
specimen of form deta has been seen by the writer in collections from 
Chautauqua or Cattaraugus counties. A \few specimens from a 
quarry south of Cuba, Allegany County, have this form. As they are 
there associated in the same rock with typical specimens of O. leconen- 
sis it is assumed that the two forms were genetically differentiated at 
the time and the name Dalmanella allegania is proposed for individ- 
uals of general likeness to D. leonensis but having the form beta as 
described beyond. 
The specimen represented by Hall’s fig. 5 is associated with typical 
forms of PD. leonensis in a series of specimens collected in the town 
of Villenova, Chautauqua County. These specimens present features 
distinct from those of ). /eonensis, and for them the name Vhiemella 
villenovia 1s proposed. 
DALMANELLA DANBYI, new species. 
Pee JUL, kes, BL, GE, Gy II4b 1s, Al, gin! 2s, 
Tn size and general form this species is very similar to form alpha 
of Orthis leonensis Hall. It differs from that species in the follow- 
ing characters: The elevated radiating lines tend to preserve the 
fasciculate character to the front, thus causing the shell to appear 
as covered by lines of differing size. (In PD. leonensis the fasciculate 
character of the lines is conspicuous near the beak but inconspicuous 
toward the front.) The lines increase by division a little more rapid- 
ly than in J). leonensis. At the front of specimens of 10 mm. length 
the number of lines each side of the middle is about 30. In specimens 
of DP. leonensis of the same size there are about 20 to 25. From the 
OU INI Mog IOV 5 IUIOT, 1 OA Jol, Walt 
