Mr. W. H. Benson on the genus Scaphula. 127 



after exit, assuming respectively the forms of Amosba and Actin- 

 ophrys. 



Fig. 14. Old cell of Euglena viridis presenting one large granuliferous 

 Amoeba instead of several small ones ; a portion of effete matter 

 left in the cell, and the Amoeba throwing its processes through its 

 crevices. 



Fig. 15. Portion of a filament of Oscillatoria {princeps, Kg. (?)), in which a 

 development of some germs of (Edogonium having taken place 

 in the midst of the cells of the Oscillatoria, they are bursting 

 through its sheath. 



Fig. 16. Furcularian rotiferous animalcule in which the tubulating cell has 

 become developed : (a) dilated round form assumed by the extre- 

 mity of the tube before bursting. 



X. — Amended Description of the Genus Scaphula, Benson, a 

 freshwater form of the Arcacea; with characters of a new 

 species from Tenasserim. By W. H. Benson, Esq. 



Since the year 1825, when the little bivalve Arcaceous shell, 

 Scaphula Celoa^, described in the ' Journal of the Calcutta Asiatic 

 Society ^ for 1836, occurred to me in the rejectamenta of the 

 River Jumna in Bundelkhund, no species has been added to the 

 genus. In the past year a rich collection of land and fresh- 

 water shells, containing many new species, was made in the 

 British provinces of Burmah, from the frontier above Prome 

 on the Irawadi to Mergui, by Mr. W. Theobald, jun., who has 

 obligingly submitted them to my examination. Among them I 

 find a very distinct species of Scaphula, with the epidermis 

 strongly developed, and the hinges joined by the ligament, as 

 was the case with one of my specimens of S. Celox, which ex- 

 hibited vestiges of a light epidermis. A conjecture has been 

 hazarded by an English naturalist, probably from the view of 

 the specimens presented to the Zoological Society in 1834, that 

 the shell was a subfossil extinct form. The present discovery 

 must set that opinion completely at rest. Besides the specimens 

 of S. Celox from the Jumna, some were subsequently procured 

 from the bed of its tributary, the River Cane, at Banda, and in 

 1835 I observed the species in a collection of shells made in the 

 vicinity of the Khassya Hills to the east of Bengal. 



The new form was found in some abundance in the Tenasserim 

 River, and we may now hope that other species will yet be 

 found in Burmah, and in the countries extending to Cochin 

 China, as they become gradually open to the naturalist. 



Scaphula was first made known in the ' Zoological Journal ' 

 for 1834. In 1840 Swainson applied the same name to a form 

 of the Olivacea, having overlooked the previous employment of 

 the term as a generic designation. The more perfect state of 



