890 riiOCEEDINGS OF THE NATIONAL MUSEUM. 



KELLIA (KELLIOLA) SYMMETROS Jeffreys. 



Kellia sijmmetros Jekfrkvs, Anu. Mag. Nat. Hist., December, 1876, p. 491. 



A. 16. From a careful inicroscoi)ic examination of the type of this very 

 minute species, I find the hinge was imperfectly observed, and hence 

 incorrectly described by Dr. Jeifreys, a fact perhaps due to imperfec 

 tion of his microscope. There is in each valve a single strong, short 

 tooth in front of the beaks, that in the left valve is thinner, flatter, and 

 fits over the more conical tooth of the right valve. Behind the beaks 

 is a strong resilium without a lithodesma. The hinge plate is narrow 

 and flat; in some lights the edge is so illuminated as to give the api^ear- 

 ance of a lamina, which does not exist. This hinge recalls that of 

 Aligena, and is quite different from that of the true Kellias, for which 

 reason I have separated it as Kelllola. 



MYSELLA PLANULATA Stimpson. 



KelUa planulata Stimpson, Shells of New England, 1851, p. 17. 



A. 17. The shell figured by Gould ' was named j)la7iul<((a by Stimpson. 

 Gould's description included not only this species, but Turtonia oninnta, 

 which, as Gould afterwards recognized, he took to be the young of the 

 larger shell which he figured. Subsequently the ijlanulata was incor- 

 rectly identified with the British Tellimya hidentata of authors. The 

 two shells are quite distinct, as the examination of a very large num- 

 ber of Mysella hidentata has convinced me. The European shell is con- 

 stantly smaller, more convex, more inequilateral, more quadrate, and 

 more elongate. It also has smaller dental lamellte than the average 

 American specimens. I have not found any adult specimens which 

 could be called intermediate, and I have therefore restored Stimpson's 

 name. The variety fragilis Verrill and Bush has feebler teeth than the 

 form which they call variety tenuis^ but differences of this kind are 

 frequent among these little shells, and too much value should not 

 be ascribed to them. Exactly parallel differences occur in all those 

 species of Mysella of which I have been able to examine a large series of 

 specimens. 



MYSELLA OVATA Jeffreys. 



Montacuta ovata ( ? Jeffreys's species) Verrill and Bush, Proc. U. S. Nat. Mas., 

 XX, 1898, p. 781, pi. xcii, figs. 9, 10. 



A. 21. The specimens so identified are incrusted with such a heavy 

 coat of iron oxide as to have become pathologically modified. They 

 resemble many of Jeffreys's specimens in this, and may really be 

 identical, but it would be more satisfactory to be able to prove if by 

 normal individuals. 



MYSELLA (TUMIDULA var.) VERRILLI Dall. 



Montacuta tnmidida Verrill and Bush, Proc. U. S. Nat. Mas., XX, 1898, p. 781, 

 pi. xcin, fig. 6 ; pi. xciv, figs. 1, 2. 



' Inv. Mass., 1841, pi. ii, fig. 33. 



