Dear Devendra,

It could be a species of Ampullaria (commonly called apple snails) probably Ampullaria cuprina.

send the view of aperture and also a straight view of the shell

What is the scale and is this a marine or freshwater shoreline?  

From the angle of the photograph these do not appear to be apple snails - apple snails are relatively low spired compared to the width of the body whorl.  I agree they look like something in the Assiminidae or possibly the Hydrobiidae families.  If they are from the Hydrobiids, I believe the only way to get to species level identifications is to examine the soft parts.  

Is the mudflat in India? Are the specimens less then 5 mm? Assimineidae might be a good guess. . . 

My opinion is:

if it is small species (under 5 mm) surely not Ampullaria...

Assimineidae

Assimineidae

Locality, biotope (freshwater? brackish? marine?), size and frontal view are required for an identification. If this shell is from India, it is unlikely a species of the Assimineidae. The only species in India is Assiminea francessi, which has 3 coloured bands on the last whorl, which is clearly not the case on the picture. The shells on the picture might be a species of the Littorinidae. 

Assimineidae.

Size, locality and apertural view would be useful for identification

http://www.conchology.be/?t=68&u=843412&g=2934dd0f3cb1b59fea4286b8c0da7123&q=10f813d585f9dcfc8a9309f0fbb063d4

Assiminea brevicula

Certainly not Assiminea brevicula. That species has a white suture, and a white umbilical region. These characters are absent in the photographs given by Devendra.

It would help  with the identification to know the size in mm, and to have a clear lateral view facing the aperture rather than this oblique view.

It is also helpful to give us more information about the locality and habitat. Thanks.

It seems to be Assiminea brevicula (Pfeiffer, 1855)

http://www.marinespecies.org/aphia.php?p=taxdetails&id=716989

We have Assiminea fasciata Benson, 1835 in the Naturalis collection from India. Could that be the species? I cannot find a picture on the internet. Ruud Bank, do you have Benson, 1835 on your bookshelf?

Assiminea fasciata Benson, 1835, Zoological Journal, 5: 463-464. This is a synonym of Paludina francesii Wood, 1828, Suppl. Index Testac.: 47, pl. 6 fig. 28. This is an Assiminea species with three coloured (red) bands on its last whorl. One can found different spellings in the literature: francesi, francessi, francisi, francessiae (all wrong).

Devendra:

Kindly furnish complete detail: different views, size, habitat, collecting region etc. As of now this can be designated as Assiminea sp. 

Best

Syed

I think this is Assiminea brevicula, if the fellow try to show the ventral view, it may easy for further confirmation.

Well, Devendra back to the field and pick up some of these criters to make a proper photo :)

excuse me but I  expert only in terrestrial or fresh water molluscs

Ivano 

It may help you for better analysis. thank you all.

Unfortunately we do not know the total height of the shells gathered by Devendra. The species belongs to the certainly Assimineidae Family. The systematic position is the following: Superfamily Truncatelloidea Gray 1840, Family Assimineidae Adams & Adams 1856, Solenomphala sp.

Devendra suggest to read the article that I attach.

Article New records of non-indigenous molluscs in the Mediterranean ...

Hi Devendra.. l agree with Dr. Amurugam, that is Assiminea brevicula..very tiny bright colour gastropod, plenty in the mangrove floor. 

I am also agree.. Assiminea brevicula is very common mangrove species in South & South-east Asia. Vary in colour from reddish to pale yellow..

No chance for proper identification of fresh or brackish water mollusks on base of such a low quality photographs. As you might know, shell structure, shape and size vary greatly in aquatic molluscs. As well, there are so many cryptic species and DNA sequencing is almost mandatory in order to identify species properly!

Yes  it's Assiminea brevicula (Pfeiffer, 1855)