ASTRORHIZIDAE 65 



On the other hand, a specimen found at St. 45 exhibits a definite instance of selection, 

 similar to Psammosplwera parva, the spherical test, which is very neatly built of fine 

 sand only, being transfixed by a very long spicule (Fig. 21). 



These projecting spicules are sometimes used as supports for the tubes which are 

 attached to them. But there is no general practice, and frequently a tube is seen growing 

 out quite close to a projecting spicule, but unattached. 



Armorella has probably a wide distribution in deep or cold waters. A similar organism, 

 though specifically distinct, has been found in several dredgings round the British Isles, 

 but always of rare occurrence. Several of the figures attributed to Thiirammina in 

 Haeusler's papers would appear to be referable to our genus, in which case its record 

 extends back to Jurassic times. 



71. Armorella sphaerica, Heron-Allen and Earland (Plate VII, figs. 16-23). 



Armorella sphaerica, Heron-Allen and Earland, 1929, etc., FSA, 1932, p. 257, pi. ii, figs. 4-1 1. 

 Twelve stations: 27, 31, 45, 123, 140, 144, 148, 149; WS 33, 154, 334; MS 68. 



The description of the genus is sufficient for the species, which is very common at 

 St. 144, common at Sts. 148, 149, frequent at Sts. 45 and 140, very rare at the remaining 

 stations. The range of depth lies between 1 10 and 270 m., except for a single specimen 

 at WS 334 in 3705 m. There is a considerable range of size, the specimens reaching 

 1-2 mm. in diameter without tubes. An average size is about i-omm. in diameter. 

 Tubes average up to 0-3 mm. in length. There can be no doubt that the small individuals, 

 which represent the species at those stations where it is rare, are merely young or 

 pauperate individuals. 



The external texture of the test varies to a lesser extent. In general the sphere is 

 smooth externally, owing to its homogeneous construction, but occasionally the animal 

 incorporates sand grains which, being larger than the thickness of the wall, project and 

 give an unfinished appearance to the test. 



The tubes vary enormously both in size and number. It is difficult to give a maximum, 

 as a broken tube may leave little trace. Specimens with four tubes are common. The 

 length of the tube has no relation to the size of the sphere : many large specimens have 

 very short tubes and vice versa. 



Genus Thurammina, Brady, 1879 



In 1917 we published a paper "On Thurammina papillata, Brady; a Study in Varia- 

 tion" (H.-A. and E. 1912, etc., NSG, No. 5, 1917) in which we expressed the opinion 

 that "all hitherto recorded species of the genus Thurammina, including Thuramminopsis 

 canaliailata, Haeusler, are referable to a single specific type, Thurammina papillata, 

 Brady", and that while "for taxonomical reasons numerous varietal names must be 

 employed. . .they have no biological significance". 



The experience of the intervening years has not caused me to vary from the opinion 

 then expressed. On the contrary, I believe that a similar intensive study of other 



