368 



MARINE INVERTEBRATES 



Polynices duplicate. 



inches ; the breadth slightly exceeds the length. P. duplicata has a very 

 extensive range, from the Gulf of Mexico to Newfoundland. The 



largest and finest specimens are 

 found in the vicinity of New York 

 and at Hatteras. In Florida they 

 are usually smaller. This species 

 cannot be confounded with any 

 other upon our coast on account of 

 the heavy callous deposit over the 

 umbilicus. Its habits are similar 

 to those of P. hcros. 



Natica clatisa. A Northern 

 species which is fairly abundant 

 on the Maine coast. It 

 has a shelly operculum, 

 and the umbilicus is 

 neatly closed by a pure 

 white, shining callosity. 

 Its length is about one 

 half an inch, its color 

 livid white tolightbrown, 

 white within. The calcareous operculum at once determines this shell. 

 This species (as well as the following one) has retained the generic 

 name of Natica because of the shelly operculum, as explained 

 below. 



2V. canrenn. One of the handsomer species of Natica, which occurs 

 in Florida. Sometimes it is seen as far north as Hatteras. The shell is 

 white, with bars of light chestnut circling the whorls, and with zigzag 

 lines of darker purplish hue crossing them. The base of the shell is 

 white. The aperture is large and flaring, and is purplish within. The 

 umbilicus is partially closed by an entering callous plug. The operculum 

 is calcareous, with eccentric, deeply cut grooves. Found in sandy sta- 

 tions just about low-water mark. (Plate LXVIII.) 



F. lewisii. A species which occurs on the west coast of the United 

 States. It resembles its New England relative P. heros very closely. P. 

 letnsii is a Northern species, and does not range south of Oregon. Pro- 

 fessor Keep mentions one specimen of the size of a six-inch globe, but 

 such dimensions are very unusual. A good-sized specimen need not 

 exceed four inches in height. 



P. reclusiana. A species well known on the southern coast of Cali- 

 fornia. The umbilicus is closed by a thick, highly polished white cal- 

 losity, and the general shape of the shell is strongly suggestive of the 

 common east-coast species P. duplicata. A large specimen is about two 

 inches in diameter. 



[There has been much confusion in the generic nomenclature of this 

 family. The old name Natica once did service for all the species ; then 

 the names Lunaiia, Necei-ita, and Polynices were applied to certain spe- 

 cial forms ; but it has been wisely proposed by conchologists to use the 

 name Natica for those forms having a shelly operculum, and to adopt the 

 name Polynices for those having a corneous operculum. Lunatia and 

 Neverita have become subgenera of Polynices.} 



