118 AMERICAN JOURNAL 



Mesalia polaris, Beck. 



Turritella erosa, Couthouy, Bost. Journ. Nat. Hist, ii, p. 103, 

 pi. iii, f. 1, 1838. 



A careful comparison of North Atlantic, Greenland, and Mas- 

 sachusetts Bay specimens with those obtained at Unga, Una- 

 lashkaj and Kodiak, has left no doubt in my mind as to their 

 identity. The only difference perceptible was that the Atlantic 

 specimens, which indubitably belong to one species, are a little 

 more polished and have a smoother epidermis than the North 

 Pacific specimens. 



Mesalia reticulata, Mighels. 



Turritella reticulata, Mighels, Bost. Journ. Nat. Hist, iv, p. 



50, pi. iv, f. 19, 1843. 

 Mesalia lacteola, Cpr., Suppl. Rep. Brit. As. p. 655, 1864. 

 ? Mesalia lactea, Moll. 



A comparison of the type specimen of lacteola, Cpr., with 

 Greenland specimens of the lactea of Moller, shows that the 

 plic?e are stronger and continued further over the whorls than in 

 the latter. This character is somewhat variable, however. 



Specimens of Mesalia exactly agreeing with the type of lacte- 

 ola were labelled reticulata, Mighels, by Dr. Carpenter, and 

 agree with Nova Scotia specimens so named by Dr. Wm. Stimp- 

 son. If reticulata be distinct from lactea, it will probably stand 

 also for the North Pacific form, with which it appears to agree 

 exactly. 



Mesalia acicula, Stimpson. 



Turritella acicula, Stm., Shells of N. England, p. 35, pi. i, f. 



5, 1851. 

 Mesalia tenuisculpta, Cpr., Proc. Cal. Acad. Sci. iii, p. 216, 



1865, partim. 



The specimens in the Smithsonian Collection, marked by Dr. 

 Carpenter as the types of his Mesalia tenuisculpta, are of two 

 species ; one, to which the " fusco-cinerea " of his description ap- 

 plies, has a resemblance to Bittium ; it is, at least, not con- 

 specific with the other, which is undoubtedly a Mesalia. The 

 latter I have compared with specimens of T. acicula, Stm., 

 named by the describer, and the two appear to be identical. In 

 both the canal is more obscure than in the typical species, but 

 still evident. 



Prof. Moerch has stated in this Journal (iv, p. 46, 1868,) that 

 the operculum of reticulata differs from that of M. brevialis, and 



