Cornxtspira diffusa. By E. Heron- Allen and A. Earland. 273 



pared with the transverse furrows of growth frequently seen in 

 such Miliolids as Miliolina suhrotunda Mont. sp. and Massilina 

 sirans d'Orbigny sp. 



The surface of the shell is white and polished, covered either 

 partly or entirely with irregularly disposed and variable strire or 

 faint cost(Te, often radially arranged ; the striae are generally most 

 strongly marked in the proximity ol the constrictions. 



The aperture is simple and extends over the entire extremity 

 of the test, whether this is wide and flattened, or brancliino- and 

 tubular. The edges of the test are generally somewhat constricted 

 in the neighbourhood of the aperture. 



The size of the test varies enormously, according to locality 

 and degree of development ; among the hundreds of specimens 

 seen both in the living and in the dry condition, there have been 

 none which could be definitely regarded as complete. The largest 

 fragments observed have exceeded 3 mm. in length or breadth, 

 according to the scheme of growth adopted, whether compressed 

 or ramifying, but 1 mm. would probably more nearly represent 

 the average size of the fragments on which our knowledge of the 

 species is largely based. 



We have been familiar for very many years with the curious 

 species described in this paper. It was first seen in the shape of occa- 

 sional fragments of small size and obscure character in some of Mr. 

 Joseph Wright's dredgings from the south-west of Ireland. The 

 specimens were, however, insufficient in number and character to 

 determine the nature and affinities of the organism. Subsequently, 

 when dredging in the North Sea and other Scottish areas, Earland 

 found the species in much greater profusion ; but even then, owing 

 to its anomalous character, it was some time before its true position 

 could be ascertained. 



For a long time no specimen was found showing any trace of 

 an initial portion, and although on other gi'ounds little hesitation 

 was felt in assigning the specimens to the genus Cornuspira, it 

 was not until the specimen figured in the centre of the plate was 

 discovered that we were able to determine its position with cer- 

 tainty. Since then one or two similar individuals showing the 

 initial spiral portion have been observed, but they are extremely 

 rare even in localities where fragments of the protean shell are 

 frequent. This would seem to point to the conclusion that the 

 formation of the normal spiral coil of Cormcsjnra is not an essential 

 part of the life-history of the species, and that the animal is able 

 to reproduce itself by the growth of any portion of the protean 

 shell, which becomes separated by fracture from the parent — the 

 essential nuclear conditions being favourable. 



In the absence of the initial portion of the shell, it was at first 

 thought that the organism was sessile in its early stages, but in 

 spite of careful search, no sessile individuals were ever found, and 



