160 Rev. T. Hincks's Contributions towards 



tected in front by a broad shield-like plate, which is continued 

 downwards for some distance within the cell ; attached to the 

 inner surface of the plate, on a level with the margin of the 

 orifice, a semicircular membrano-calcareous (?) frame, into 

 which the oral valve fits ; wall of the cell elevated behind the 

 orifice into a broad hood-like expansion, which covers it in 

 and forms an arched secondary orifice. Zoarium (in the only 

 known species) erect and bilaminate. 



Aspidostoma crassum, n. sp. 

 (PL X. figs. 6, 6 a.) 



Zoarium erect, compressed, thick, contracted towards the 

 base, and widening upwards, of a reddish-brown colour. Zo- 

 cecia disposed in two layers, placed back to back, massive and 

 thick-walled, quincuncial, very broad and rounded above, 

 narrowing off downwards (pyriform), truncate at the bottom, 

 divided by very deep sutures ; surface dense, roughened ; 

 back of the cell elevated and forming a hood over the orifice, 

 with an arched opening in front, the margin of the hood I'ising 

 into two prominent pointed processes, between which there is 

 a narrow cleft ; orifice arched above, straight below, screened 

 by a broad plate, with a thickened and everted edge, which 

 conceals it and stretches across a great part of the arched 

 opening ; margin of the plate continuous with the wall of the 

 hood, and forming with it on each side a loop-shaped opening ; 

 front of the cell somewhat flattened below the orifice and 

 sloping down towards it ; in the centre of this portion a raised 

 elongate callosity ; leaning against the side of many of the 

 cells, a little below the upper extremity, an avicuJarium^ with 

 a very short, broad, subtriangular mandible directed upwards. 

 Ocecium elongate, much depressed, shield-like, granulated. 



Loc. Dredged between Patagonia and the Falkland Islands 

 {Gapt. Cawne Warren). 



This very curious form is remarkable for the thickness 

 and solidity of the zoarium and the massive character of the 

 zooecia. Young cells are less strongly calcified, and the hood 

 is of much more slender make than in the adult, and does not 

 project so far in advance of the orifice. It is always at this 

 stage destitute of the marginal processes which give so 

 peculiar a character to the adult zoarium*. In the old cells 

 calcification is carried to a great extent, the upper extremity 

 becomes very tumid, and the wall rises down the sides into a 

 kind of mound, which partially closes in the depressed area 

 below the mouth. The curious structure of the orifice will 



• The figures do not show the very prominent and striking character 

 of the hood, and its two marginal processes. 



