58 THE NAUTILUS. 



rayed po.-tei -iorly, usually somewhat pointed behind, the females dis- 

 tiugui>hed from the males by a well-developed basal swelling, and 

 the beak sculpture consisting of parallel, curved ridges, which are 

 drawn in towards the hinge-line posteriorly, and are more open 

 anteriorly. The cardinals are usually compressed, often torn and 

 reflected upwards, and the nacre is generally brilliant bluish-silvery, 

 becoming richly iridescent behind, but it is sometimes purple. The 

 peculiar beak sculpture, much like that of the Tetralasmus group, 

 is one of the best characters when not eroded away. 



Mr. Call is right in his criticism on my paper on the UnioniclcBof 

 Florida, in which I placed Unio trogxii'iix Lea and U. /</</'<///. 

 Gould in the Parvus group. At the time of writing that paper I 

 hud carefully examined all of Lea's material, all the general collec- 

 tion of the National Museum, much of B. H. Wright's, Mrs. George 

 Andrews', AY in. A. Marsh's, Rev. A. Dean's and my own collection 

 of Florida and Georgia Unios of this general type, but bad not 

 found a specimen old or young that showed the beak sculpture. 

 Recently, in examining some specimens of U. amii//ilalniit in Mr. A. 

 G. Wetherby's collection, from Clear Lake, Florida, I noticed that 

 the lieak sculpture was perfect, and consisted of a double loop, hence 

 they cannot be placed in the Parrii* group. I may remark, in 

 passing, that having seen Gould's type of U. lepidus, I should un- 

 hesitatingly pronounce it the same as Lea's amygda/mn. 



Unfortunately, Mr. Barnes' description of Unio pur run' is very 

 brief and imperfect, and the only figure he gave of it is an outline. 

 Much eonfu.-ion exists concerning this species, and it is often con- 

 founded with Unin texasensis; in fact, Mr. Lea himself has placed a 

 lot of specimens of the latter species from northern localities among 

 tin' parvus iu his own collection. Unin texasensis certainly extends 

 into southern Indiana and Illinois, and well north into Missouri and 

 Kansas. In general, U. JHUTIIX is smaller than U. texasensis, is more 

 inflated and cylindrical, rather more elongated, and has a much 

 more evenly rounded posterior region. The latter is almost al\\a\> 

 ili-tinctly pointed behind. 



I cannot asirec with all of Mr. Call's synonomy. I have all of 

 Lea's tvpe> of this and related groups before me. I'. ni<ir</iinis Lea, 

 and I'. r,-iun'i t/i Lea. are probably the same, and arc, no doubt, 

 nn-mhers of the I'HITUX group, but are widely different from U. par- 

 i'u>s, in which he places the former, as they are shorter, less inflated, 



= Am. .11. Science ami Arts. VI. 1823, }*. 17-1. pi. XIII, lig. 1*. 



