450 MR. ST. GEORGE MIVART ON THE [June 24, 
fusco-olivacea, concentrice plicato-striata, disco medio et postico 
rugis obliquis irregulariter angulatis, interdum granosis, hic illic 
presertim versus marginem ventralem obsoletis corrugato ; umbo- 
nibus non prominentibus, subplanulatis, angulatim corrugatis, haud 
procul ab extremitate anteriore positis ; lunella parva, concava ; 
latere antico brevissimo subacuminato-rotundato ; area conveza ; 
margine dorsali postice regulariter convexo-curvato, terminaliter 
rotundato, ventrali convexo; dentibus cardinalibus crassis, radiatim 
corrugatis, in valva dextra binis, anteriore minimo, in sinistra 
ternis vel subternis ; lateralibus elongatis subcurvatis, in valva 
dextra subduplicibus, in sinistra duplicibus ; margarita colore 
salmonis tincta. Testa junior rotundato-ovalis, omnino preter ad 
extremitatem anticam subradiatim granoso-plicifera. 
1. 2. 3 (Testa junior). 
OR aed ents a hea 52 45 34 
Da ts Be ris hacipen dis ial Gi EEE 32 263 
Origa 0 eee /.. 22 20 17 
Ligamenti long......... 23 - 205 16 
Hab. in flumine Iravadi ad Bhamo in regno Ave. 
I know of no Unio with which I can compare this. U. pellis 
lacerti, Mor., from Siam, is a little like it, but is much narrower and 
less inequivalve. 
Several other species of Unio occurring with U. burmanus appear 
to me to be rather varieties of named species than forms deserving a 
distinct name. In one or two cases I feel doubtful, however. All 
would unquestionably be described as new by many naturalists. It 
is worthy of note that some of them are more closely allied to forms 
occurring in the Brahmapooter river, in Assam, than to those inha- 
biting the lower Irawady valley, in Pegu. The land shells of Bhamo 
and its neighbourhood are mostly either identical with forms occur- 
ring in Cachar and Khasia, or closely allied to them; and it is a 
remarkable and interesting fact connected with freshwater shells to 
find that they coincide in their distribution with the land animals, 
and do not follow the lines of the rivers in which they live, thus 
adding another proof of the existence of a means of migration 
amongst them independent of the course of rivers. 
7. Notes on the Myology of Menobranchus lateralis. By 
Sr. Georce Mrvarr, F.R.S., Lecturer on Comparative 
Anatomy at St. Mary’s Hospital. 
The specimen which has served me for examination is one of 
those mentioned in my paper on Menopoma as having been confided 
to me from the stores of the Royal College of Surgeons. 
This well-known species with permanent external gills has a 
more slender form than Menopoma; it has also a narrower head and 
