The fauna of the Chazy limestone / by Percy E. Raymond.

  • Raymond, Percy Edward, 1879-1952.
Date:
[1905]
Catalogue details

Licence: In copyright

Credit: The fauna of the Chazy limestone / by Percy E. Raymond. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    20/32 (page 370)
    Ordds acufiplicata sp. nov. Shell small, almost circular in outline. IIin<re width not quite e(|ual to the greatest widtli l)elow. Cardinal area of ventral valve high and a little I’etj’orse. Foiaimen nari’ow and open. Ventral valve strongly' convex, highest on the umbo. Dorsal valve convex on tlie nmho, flattened in fi'ont. There is a shallow sinus on this valve, which is naiTow at the beak but l)ecomes wider in fi-ont. Surface marked by to 15 sharp simple striic separated b}^ spaces wider than the stripe. Locality.—South end of Yalcour Island. The types are in the writer’s collection. Ploisiomys strophomenoules sp. nov. Shell small, ventral valve convex at the umbo, concave in front. Dorsal valve convex, with a narrow sinus on the umbo, hut frequently with a slight fold on the front of the shell, in which case the ventral valve shows a shallow median sinus. Surface marked by numerous fine stripe, which increase by bifurcation and implantation. There are usually 7 or 8 in the space of 2 millimeters on the middle of the front of the shell. The cardinal ai*ea of both valves is low. The ventral area has a narrow delthyrium, whicli at the apex is perforated for the passage of the pedicle. The interior of the ventral valve shows small but strongdv marked muscle scars under tlie umbo. The muscle area is roughly quadrate and contains a pair of strong diductor scars, between which are the narrow aclductor attachments. Posterior to the latter is a deep ])edicle scar. The lateral edges of the diductor scars are bounded by strong plates, which run back to support the dental lamellpe. The interior of the dorsal valve sliows a rol)ust, simple cardinal pro- cess and small dental sockets bordered by strong plates which do not greatly diverge. In front of the cardinal process is a low but strong median ridge, on either side of which are the four scars of the adductor, not, however, deeply impressed. J^ocality.—Crown Point, Plattsburg, and Yalcour Island, New York. The type is from the quarries near the Platts- burg Fair Grounds and is in the Carnegie Museum. a O llchertella exfoliaia sp. nov. This shell is distinguished from Ilehertella costalis hv its smaller size, more pronounced dorsal sinus, and by the fact that the stripe are always sim]de instead of bifurcating. It differs from II. horealis in its smaller size, and in the narrow^ and deep dorsal sinus. Locality.—Common in the lower part of the Chazy at Chazy and Yalcour Island; also at Plattsburg, Yalcour, and Isle La Motte, New York. The type is in the Carnegie Museum.