Cryptosemulus gracilis Collinge, 1902  

Collinge (1902) original descriptions on Cryptosemelus gracilis – “Animal dark blue, body marked by prominent oblique lines running downward and backward, dorsum posteriorly keeled; mantle rises upon the shell anteriorly and laterally, on the right side it is produced into a wing-like extension covering the apex of the shell, while on the left side antero-laterally there is a smaller lappet. Rugae only visible on the head and anterior parts of the body. Caudal mucous pore very small. Peripodial groove distinct. Foot-fringe bright yellow, no lineoles. Foot-sole divided into median and lateral planes. Shell yellow, thin, membranaceous, whorls, 3 ½, last whorl very large.”