MUSEUM OF COMPARATIVE ZOOLOGY. 203 



to the transverse, and taking on in this way a more reticulated appearance. It 

 has been confounded with a closely related, but quite distinguishable, West 

 American species, Eupleura muriciformis Broderip, or clathrata Gray. The 

 latter (A) is a considerably larger shell when adult, and may be distinguished 

 from E. caudata (B) by the following characters. 



A. Larger (circa 40.0 mm.); strongly three-noduled on the back of the last 

 whorl, the middle nodule most prominent, giving the shell a trigonal aspect 

 when viewed from the apex of the spire ; a second primary varix frequently 

 found behind this middle nodule, or near it ; line of the nodules represented 

 by a keel on the varix, which terminates in a strong recurved hook, grooved 

 in front, with no teeth behind this groove, or between it and the body whorl, 

 inside the aperture; aperture tapering gradually into the canal, and therefore 

 ovate-pyriform. 



B. Smaller (max. circa 28.0 mm.), with two strong or several obscure nod- 

 ules on the back, all the varices nearly in the same plane, so that the shell is 

 not trigonal but flattened-ovate viewed from the apex; the keel from the line 

 of the nodules does not materially interrupt the rounding over of the varix to 

 the body, though the young have a small spine here, which is not grooved in 

 front, and the denticulations of the aperture extend quite up to the body, and 

 there is even one on the callus overlaying the body whorl itself; the varices 

 are broader, the mouth shorter and rounder, and more contracted at the begin- 

 ning of the canal. 



The comparison should be made in all cases with fully adult specimens; the 

 young, and those specimens in which the callosity of the mouth is not fully 

 complete, are very close to one another, especially if Floridian specimens are 

 compared with those from the west coast of America. This is, however, only 

 what we should anticipate with two forms which in all probability are de- 

 scended from the same ancestors, and have become differentiated within a 

 comparatively short geological time. The soft parts of Eupleura caudata are 

 of a yellowish white color with opaque white dots and mottlings. The ten- 

 tacula taper from base to tip, with the eyes about midway, not showing any 

 enlargement. The foot is short, truncate in front, rounded behind. The verge 

 is behind the right tentacle, turned back in a curve like the outline of the 

 concha of the human ear. It is compressed at the base, thick, rounded and 

 blunt at the tip, the transverse diameter subequal throughout. The egg cap- 

 sules, like those of many Muricidaz, are pedunculate on a long slender pedicel, 

 like a three-sided prism, swelling above, one keel rounding off and sending 

 bifurcations to the other two, which are unequally prominent, the right or 

 highest one terminating in a minute circular aperture, the left in an acute 

 point. There are 12 to 20 very minute dark eggs in each capsule. They were 

 taken by Dr. Stimpson at Beaufort, S. C. The wide difference between these 

 and the flattened circular capsules of Trophon (see Jeffreys, Brit. Conch., IV. 

 pi. viii. fig. 2) is apparent. The operculum is chestnut-brown, and like that of 

 Murex or Pteronotus, not like that of Trophon. 



