454 MR. F. CHAPMAN OK HADDOIiflA, 



Haddonia toreesiensis, sp. nov. (Plate 28.) 



Test calcareo-arenaeeous, surface rough, of a whitish to yellow 

 or brown colour ; consisting o£ imperfectly septate chambers, 

 their breadth being about twice their height, which are here and 

 there subdivided obliquely, somewhat in the manner of Textularia, 

 but very irregularly, the general plan being a moniliform series 

 of segments. The test commences either with a straight or a 

 sinuous series of chambers, or more rarely with a flat coil of a 

 single whorl, after which the chambers are arranged in a more 

 or less rectilinear manner. The test is adherent to coral- 

 rock, fragments of which, with quartz-grains and organisms 

 such as Discorbina, fragments of Polytremata, and pieces of 

 molluscan shells, are used to construct the shell-wall. The 

 sinuous manner of growth in Haddonia is suggestive of a Serpula- 

 tube, and the shell is often bent upon itself. The interior of the 

 test is smooth or even polished, and j)artially subdivided by 

 imperfect and curved septa (irregularly labyrinthic). The outer 

 wall of the test is perforated by coarse pores such as are ?een in 

 JRupertia iu the hyaline group ; and the salient angles of the 

 imperfect septa, which form flying buttresses on the interior of 

 the proper wall, usually show in section a layer of transparent 

 (hyaline) prismatic shell-straicture whirh is non- perforate. 



Aperture usually crescent-shaped, sometimes gaping, but more 

 often having a valvular flap, formed by a prolongation of the 

 superior surface of the test, which nearly closes up the orifice as 

 in Valvulina and some of the Miliolinee. This apertural flap or 

 valve is in some specimens directed towards the distal end of the 

 test (PL 28. fig. 1), but in others towards the proximal end {cf. 

 fig. 3) ; in other words, the organism is sometimes adherent by 

 one side of the flattened and asymmetrical test, and at other 

 times by the relatively opposite side. In the one case the 

 extruding sarcode will be directed towards the surface of attach- 

 ment, in the other away from it. 



The last few chambers also communicate with one another by 

 a curved slit in the middle of the transverse septal wall, when the 

 septation is more than usually complete. 



The sarcode when dry is of a rich brown colour (as seen in the 

 recesses of the test o^ Haddonia in a section), with cavernous or 

 honeycomb structure, and bearing here and there fragmentary 

 sponge-spicules, which are adventitious. 



Length 5 to nearly f of an inch. 



On coral-rock, Torres Straits. 



