672 EXPLANATION OF PLATES. 
PLATE XXXVI. 
Fig. 1. Unio cuprinus, Lea, var. subventralis, n. (p. 506), Tabasco: 14, seen ) 
from above. 
2. aztecorum, Phil. (p. 502), normal form, Rio de Misantla : 
26, seen from above. . . a, right valve, 
3. —— , young specimen, Rio de Misantla. inside. 
4, —— , large specimen, Playa de Misantla. 
5. —— , var. chapalanus *, n. (p. 504), Laguna de Chapala. 
6. —— tehuantepecensis, Cr. & Fisch., var. copanensis, n. (p. 502), Rio 
Copan. J 
PLATE XXXVII. 
Fig. 1. Unio aztecorum, Phil., var. strebeli, Lea (p. 508), Playa de Misantla, ) 
full-grown specimen from Strebel’s collection. 
9 a, right valve, 
, ditto, younger specimen from the same locality. 
(p. 502), Playa de Misantla, very old specimen: 3 4, seen 
from above. 
inside. 
4 
PLATE XXXVIII. 
Fig. 1. Unio ravistellus, Morel., var. vere-pacis, Tristr. (p. 516), Vera Paz, | 
Tristram’s type-specimen. 
2-6. (p. 516), Lake of Yzabal, different forms chosen from 
a large number of shells collected by Dr. O. Stoli: 5 a, younger, 
6 a, less worn, specimen. . 
7, 8. guatemalanus, n. (p. 519), Paso Antonio, two specimens of @ : ight valve, 
somewhat different form: 7 6, 8b, seen from above. side. 
9. championi, n. (p. 508), Paso Antonio. 
10. goascoranensis, Lea (p. 501), Paso Antonio: 100, seen from 
above. 
11. hjalmarsoni, n. (p. 509), Rio Chamelicon. 
PLATE XXXIX. 
Figs. 1, 2. Unio aratus, Lea (p. 499), Lake of Managua, specimen given by ) 
Dr. O. Stoll to the Berlin Museum (this locality is omitted in 
the text) : 2 6, seen from above. 
3. —— , Specimen given by Largilliert to the Berlin Museum: > 
3b, seen from above. 
pliciferus, Lea, var. minor, Fisch. & Cr. (p. 515), Rio Medellin, 
collected by Strebel. J 
a, right valve, 
inside. 
4. 
* Incorrectly named U. aztecorum, var. chapalensis, on the Plate. 
