F. Haas; Beiträge zu einer Monographie der asiatischen Unioniden, 
201 
This species is very closely allied to Physunio micropterus (Morelet), with shells of which 
from Cambodia I have compared my specimens. It differs, however, in the form of the hinge, 
in its even less produced wing, in its less prominent umbo and darker coloration, 
Annandale, 
Ich begnüge mich mit der Wiedergabe der Originaldiagnose dieser mir unbekannt geblie- 
benen Art, die aus Zuflüssen des in den südlichen Shanstaaten, in einer Höhe von etwa 1000 m. 
gelegenen Inlé-Sees stammt. Ohne authentische Stücke gesehen zu haben kann ich mir kein 
sicheres Urteil bilden, doch scheint mir aus der Beschreibung und den Abbildungen hervorzu- 
gehen, daß micr opt er aides dem miropterus Morelet sehr nahe steht und wohl nur dessen nörd- 
liche Lokalform darstellt. Den nun folgenden Physunio ferrugineus Annandale kann ich nur als 
die Seeform von micr opter aides auffassen. 
Zur Ergänzung der von mir im Conch. Cab,, S. 275 gemachten anatomischen Angaben über 
die Gattung Physunio lasse nun folgen, was Prashad (a. a. 0.) über das Marsupium und das 
Glochidium von micr opt er aides und ferrugineus sagt (S. 184 — 185): 
In both the species only the middle region of the outer gills is specialized to serve as a 
marsupium, while a larger posterior and a much smaller anterior portion retain the ordinary 
respiratory character. The marsupial region in both species is much swollen and in the preser- 
ved specimens is of a creamy colour. It is clearly marked off from the anterior and posterior 
respiratory regions. In P. micropteroides 17 water-tubes are modified to serve as a brood-pouch, 
while in P. ferrugineus only 11 are thus modified. 
The characters of the marsupium of the genus may be summed up as follows. Marsupium 
formed by 11 — 17 simple water-tubes in the middle region of the outer gills, leaving a larger 
posterior and a much smaller anterior unmodified portion for respiration. 
The glochidia of the 2 species differ mainly in size. In the case of P. micropteroides a 
glochidium measures 0,32 mm. by 0,29 mm., while that of P. ferrugineus is much smaller, being 
0,28 mm, by 0,26 mm. The glochidium of P. micropteroides is described here in detail. 
The glochidium is of the hookless types. It has the usual 2 shell valves. As seen in lateral 
view, the shell is semi-circular with a curved lower margin and an upper hinge-line. This line 
is nearly straight in P. ferrugineus, a little curved in P. micropteroides. The shell is thin in the 
middle and all over except along the hinge-line and the border, where it shows a distinct 
thickening. The whole surface, except the border, is finely granulated. From the inner edge of 
the ventral border a continuous flange projects inwards; seen from the anterior or posterior side 
this flange appears as a pointed tooth, but it is a continuous structure all along the margin. It 
shows very fine ridges on its ventral surface. Amongst the hookless glochidia like the present 
exemple this flange must serve the same purpose as the tooth in the hooked glochidia, though 
perhaps in a less efficient manner. Between the 2 valves of the shells a ligament is present 
and can be easily distinguished in sections and stained preparations. 
10. Physunio {Physunio) ferrugineus ANNANDALE. 
Physunio ferrugineus Annandale, Rec. Ind. Mus., XIV, 1918, S. 139, Textfig, 3, Taf. 19, Fig, 4 — 9. — Prashad, 
a. a. O., XIV, 1918, S, 183 — 185, Taf. 22, Fig. 10 — 11 (Marsupium und Glochidium), — Ghosh, a. a. O., XV, 
1918, S, 109 — 122, Taf. 16, Fig, 3, 3a (Anatomie). 
