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AMERICAN JOURNAL 
toward Gadinia in theii’/rounded forni, but are more closely 
allied to thè SipJionariidce. They cannot he aflBliated to thè Pa- 
tellidce or Tecturidce. The following species were enumerated in 
thè paper alluded to, as having been definitely identified as be- 
longing to this genus : A. borealis, Morton ; A. sexsulcatus, 
alveolus, patelliforviis, and subovatus, all of Meek and Hayden. 
The student who desires to pursue thè subject further, will do 
well to consult thè Conchologia Iconica and thè list of species of 
Siphonaria given by Hanley in thè Proc. of thè Zool. Society of 
London, 1858, page 151. 
Reperences to Peate 4. 
Fig. 8. a, side view of Sipli. thersites, with thè shell removed. 
b, view of same in thè shell, from below. 
Fig. 9. Nervous System of Siphonaria Tristensis, Sby. 
Fig. 10. Dentition of Siphonaria [Siphonaria) alternata, Say. 
b, Rhachidian tooth. 
a, section of 17th lateral. 
Fig. 11. Siphonaria [Liriola) peltoides, Dall ex Cpr. 
a, from above, enlarged one-fourth. 
b, side view. 
Explanation op Peate 5. 
Fig. 1. Dentition of Siphonaria {Liriola) tristensis, Sby. 
1" a, side view of 45th tooth. 
1" c, “ “ “ Ist lateral 1" b, section of do. 
Fig. 2. Dentition of Siphonaria {Liriola) thersites, Cpr. 
1' a, side view of Ist lateral. 
Fig. 3. Digestive and generative organs of Siphonaria tristensis, 
Sby. From above. 
a, anus. 
b, genital bladder. 
c, crop. 
g, genital papilla, 
m, buccal mass. 
0 , ovary, 
r, rectum. 
st, stomach. 
j, jaw. 
1, 1, 1, boundary of liver. 
1, a, left adductor muscle. 
r, a, right “ “ 
p, a, posterior adductor. 
p, penis. 
s, salivary gland. 
t, testis. 
