ESCHARID.E : SALICORNARIA. 357 



At a subsequent period Mr. Ilassall states, that, on a careful re- 

 examination of his specimens, he had in no case found other than 

 rhomboidal cells in S. faiximinioides, or spathulate or modified spa- 

 thulate cells in S- sinuosa ; and my own experience tends to corro- 

 borate Mr. Hassall's o2)inion. Nevertheless the real specific distinct- 

 ness of the species is undetermined. " The shape of the cells," says 

 Ellis, " is not always of a lozenge figure : sometimes we find them 

 arched at top, and sometimes of the shape of a coffin." But the evi- 

 dence here is not conclusive, for Ellis may have found these differ- 

 ently shaped cells on different specimens. Mr. Macgillivray, how- 

 ever, states that he has found them all on one polypidom. He says, 

 " By a careful examination of a very fine specimen selected from an 

 extensive series, I have found a great variation in the form of the 

 cells. These are generally 'rounded above and excavated below for 

 the reception of the head of the succeeding cell,' as they are describ- 

 ed by Mr. Hassall, but between this form and a perfect rhomboid 

 there exists an obvious gradation. Rhomboidal cells are found 

 chiefly upon the terminal articulations, but occur also throughout 

 the polypidom along with the much more numerous spathulate cells. 

 In Mr. Hassall's specimens the aperture was invariably 'situated in 

 the upper third of each cell / in mine, however, the aperture is oc- 

 casionally ' exactly central ; ' it often commences at the middle of 

 the cell, although still more frequently at a little above this." — Mr. 

 Couch is another authoritative witness to the same efiect. After 

 mentioning the variations in size to which the polypidom is subject, 

 he adds, — " The cells also are liable to considerable variations, not 

 only in different specimens, but in diff"erent parts of the same. Thus, 

 those cells at the inferior portion of the branches are quadrangular 

 most commonly, while at the upper parts the superior angle is ex- 

 panded into an arch, and hence resembles the cells of Elustra foliacea. 

 It would almost seem as if there were two species confounded under 

 this name ; but, although they differ so much in size, I have been 

 unable to discover any specific distinctions between them. The 

 cells can offer no guide in determining this point, as they vary so 

 much in the same specimen." 



Heteropora septosa, " polj'pidom boletiform, irregular, sometimes investing ; 

 pores irregular," 5. V. Wood, in Ann. and Mag. N. Hist. xiii. 14. — Mr. Wood 

 remarks of his fossil specimen of this zoophyte, that it " corresponds with a recent 

 British species in my possession upon an Area lactea." — I do not know the species. 



