NATURAL SCIENCES OF PHILADELPHIA. 147 
The second grand division contains those genera having a jaw. 
In this division also we find some genera with aculeate, and some 
with quadrate, marginal teeth. 
Of the former are: Limasx,' Ibycus,? Parmacella,’ Tennentia,' 
Mariella? Parmarion,’ Dendrolimaxz,' Phosphorasx 2? Urocyclus ?° 
{I know nothing of the position of Othelosoma, Aspidorus, and 
other problematical genera.] Vitrina,'° Vitrinoidea,” Vitrinopsis,” 
Nanina,” and all the genera now recognized in its disentegration, 
Stenopus,* Vitrinoconus,” Macrocyclis,® Zonites." 
The following genera have quadrate marginal teeth. They may 
be readily grouped by the character of their jaw, which is either 
in one single piece, in one single piece with an accessory upper 
quadrate piece, or in numerous pieces. 
Those whose jaw is in one single piece may again be subdivided 
into several groups based on the absence, presence, and peculiari- 
ties of the ribs on their jaw. This division, however, is unsatis- 
factory, as these characters are not always well marked. 
(a) Jaw without ribs: Philomycus, Parmella?® Oopelta,” Ana- 
derus,”" Sagda,” Patula,* Polymita,* Hemitrochus,” Helicodiscus.” 
1 See this paper. 
2 Heynemann, Malak. Blatt. X. 142, pl. I., fig. 3. 
3 Semper, Phil. Archipell. 90. 
Semper. cs 1 pla Vil) he. 17 DB Mo, IP 
S WO. D5 Tolle Wiles ier, 110, 
7 Heynemann, Malak. Blatt. XV., pl. I., fig. 1. 
8 Jaw and tongue not known. 
9 Heynemann, Malak. Blatt. 1866, 70, pl. XI., as Parmarton flavescens. 
0 See this paper. 
1! Semper, 1. c. 85, pl. [X., fig. 38. 
2 Thid. 86, pl. XI., fig. 26. '3 Tbid. 
1S ISN, Arne, JbAy@, INS lel OE ING Wag WIDDKS wats files, 
 sremonynee, I Goo Wily oll, QIlog Fale, Biel 
16 See this paper. % See this paper. 
8 See this paper. 
9 Jaw and lingual dentition unknown. 
” Heynemann, Malk. Blatt. XIV., pl. I., 2. 
21 Heynemann, Malk. Blatt. X., 138, pl. I., fig. 1. 
2 Bland and Binney, Am. Journ. Conch. VI., 177. 
23 See this paper. 
4 Bland and Binney, Ann. Lyc. N. H. of N. Y., X.,341, pl. XVI, fig. 1. 
2% See this paper. % See this paper. 
