1920. | N. ANNANDALE: Gastropod Molluscs. 149 
Brocchit, Ehrenberg, and Physa (Isodora) lirata, Mousson, and distin- 
guishes the latter by its more elongate body-whorl, regular spire, 
less distinct and less scalariform whorls, by the mouth of the shell 
being obtuse both above and below, and by the sculpture, which he 
describes as consisting of fine, sharp costae, which are somewhat 
distinct and represent lines of growth. The spiral and the form 
of the mouth in B. contortus (of which Istdora brocchit, Ehrenberg, 
is a Synonym) are so variable and the sculpture so liable to be less 
or more distinct in different phases and individuals that I am in- 
clined to regard these two forms as specifically identical, especially 
as I do not find that strong sculpture of the surface is always 
correlated with a more tightly wound shell or with any particular 
outline of the mouth. 
Bullinus contortus (Michaud). 
1874. Physa (Istdora) Brocchiz, var. approximans, and P. (1) livata (2), 
_Mousson, op. cit., pp. 42, 43, 
1918, Bullinus contortus, Annandale, op. cit., p. 168, pl. xx, figs. 6-11. 
1919. Bullinus contortes, Boulenger, /nd. Fourn. Med. Res., VII, p. 19. 
1919. Bullinus contortus, Kemp and Gravely, tom. cit., p. 255. 
The varietal or subspecific name approximans, M ousson, may 
perhaps be retained provisionally, but it seems probable that it 
represents a mere phase the peculiarities of which are due to life 
in water of abnormal chemical composition or to some other cir- 
cumstance of the environment. The most marked feature of this 
phase is the extreme variability of the shell, but a precisely similar 
variability occurs in a series of shells collected in Lake Ashangi 
in Abyssinia by the late Dr. W. T. Blanford. These shells are 
considerably larger than the majority of those from river-deposits 
in Lower Mesopotamia, but Capt. Boulenger obtained fresh shells 
almost as big in a drying marsh 5 miles S. of Amara and in a 
recently dried irrigation channel close to the River Tigris at the 
same place. The largest specimens in these series are 2 mm. long. 
It is curious that the species has not been found alive in 
Mesopotamia, but Capt. Boulenger’s specimens from Amara are 
entirely recent. Some of them even contain remains of the soft 
parts. B. contortus is a bottom-loving mollusc and perhaps in 
Mesopotamia, like Melanotdes tuberculatus in the Lake of Tiberias,! 
it only lives in comparatively deep water. 
Capt. R. B. Seymour Sewell, I.M.5., recently obtained a large 
shell of B. contortus (empty) near Gaza in southern Palestine, 
while I have no doubt that Preston’s Physa tiberidensis from the 
Jordan just north of the Lake of Tiberias is identical with the 
closely allied species or variety B. dybowskit. 
! Annandale, Fourn. As. Soc. Bengal (n.s.) XI, p. 466 (1915). 
— EEE 
