416 Mr. H. J. Ccarter on remarhahle Forms of 



characters of the skull and dentition. Mus tasmanie7isis, 

 Kreti't *, " a new species of land-rat discovered by Mr. George 

 Masters on the banks of the Ouse river," is no doubt one of 

 these four ; but even if the type is found to be the same as 

 one of the species here described, Mr. Krefft's name for it 

 cannot stand, as no description whatever has ever been pub- 

 lished of it. 



XLV. — liemarhabh Forms of Cellepora and Palythoa from 

 the Henegamhian Coast. By H. J. Carter, F.R.S. &c. 



[Plate XVL] 



Cellepora senegamliensis^ n. sp, (PI. XVI. fig. 1, a~v.) 



Zoariura asteroid, many-armed, about 2^^ inches in diameter, 

 Avith a large hole at the base of the arms (PI, XVI. fig. I). 

 Composition calcareous. Stracture hard, firm. Colour white, 

 spotted with greenish brown. Consisting of ten cylindrical 

 arms, variable in form, size, length, and position, some- 

 times bifurcated. Built upon a depressed, turbinoid, littorine 

 shell, over the whole of which — with the exception of the 

 aperture, which is subcircular, about l-3rd of an inch in 

 its longest diameter, and still remains open (fig. 1, a) — the 

 polyzoon has grown. Arms solid, composed throughout of an 

 aggregate of white or colourless cells (zooecia) , heaped together 

 irregularly in the form mentioned, mixed with others of a 

 greenish-brown colour, which, grouped together, retain a radi- 

 ating (? spiral) arrangement from the axis (which is also com- 

 posed of the same coloured cells) to the surface (fig. l,/*'), 

 where they terminate in subverruciform gentle elevations 

 (fig. 1, hh)y varying in size from 1 to 2-12ths of an inch in 

 diameter, and disposed more or less quincuncially about the 

 same distance apart, but chiefly collected at the extremity 

 of the arm. Zooecium conical and erect, or oval and recum- 

 bent (fig. 1, c c c c) ; orifice circular, constricted unequally, the 

 smallest ]iart (sinus) posteriorly (fig. l^ddd and 7»), margined 

 by a smooth, round, even rim, bordered in front by two or 

 more tubercles (fig. 1,^, and behind by a prominent conical 

 rostrum (fig. 1, A), against which the sinus rests more or less 

 per])endicularly (fig. 1, ^') ; furnished with a chitinous opercu- 

 lum. Surface of the cell covered witli a branclied anastomo- 



* Fauna of Tiipmania, p. ^ (1808). 



