Ai!T. 15 NEW MARINE MOLLUSKS FROM PANAMA — BARTSCH 7 



Genus ENGINA Gray 



I'LATE 1, FlGTJRE 6 



The genus Engina was defined by Gray in the Zoology of Beechey's 

 Voyage (1839, pp. 112-113). Two species were mentioned here, both 

 cited as coming from the Atlantic Ocean. The first of these, Engina 

 sonata^ was later designated as type by Gray. Since there seems to 

 liave been some confusion about the group, I take pleasure in pub- 

 lishing a photograph of the type species obtained from the British 

 Museum of Natural History, where it is resting, whicli has been 

 made available to me through the courtesy of Doctor Robson. This 

 figure is reproduced on Plate 1, Figure 6. The specimen measures 

 27.5 mm. in length. 



There are several species of Engina from the Panama region, 

 which appear to be undefined. I shall therefore give descriptions 

 and figures of some of these below. 



ENGINA PANAMENSIS, new species 



Plate 1, Figxtre 7 



The shell is of medium size. The nuclear whorls are white, the 

 rest of the shell marbled with dark chestnut-brown, yellowish white, 

 and orange. Interior of aperture bluish white. Nuclear whorls 2.6, 

 strongly rounded, smooth, separated by a moderately impressed 

 suture, forming a moderately elevated apex. The postnuclear whorls 

 are appressed at the summit, leaving the suture inconspicuous, and 

 are marked by broad, low, rounded axial ribs, of which 11 occur upon 

 all the turns. These ribs are crossed by numerous rough incremental 

 lines. The spiral sculpture consists of three strong cords, which are 

 equal on the first whorls and which render the axial ribs decidedly 

 nodulose at their junction. Beginning with the second whorl, the 

 spiral cord at the summit becomes enfeebled and the two anterior 

 to it much increased in strength. On the succeeding turn a third 

 spiral cord appears posterior to the suture, which is almost as strong 

 as the two preceding it, the posterior spiral cord near the summit 

 practically disappearing. These strong spiral cords render the ribs 

 decidedly nodulose, the nodules having their long axis parallel with 

 the spiral sculpture. In addition to the strong cords the entire 

 surface of the shell, on spire and base, is marked by rather strong, 

 more or less irregularly developed spiral threads, which are a little 

 heavier than the incremental lines, the two forming a reticulated pat- 

 tern. Periphery rendered somewhat angulated by the third spiral 

 cord. Base moderately rounded, between the insertion of the col- 

 umella and the periphery, marked by three almost equal and equally 

 spaced spiral cords, which are almost as strong as the anterior one 



