REPORT ON THE DIATOMACE^. 19 



which are very transparent, presents a central inflection which seems to indicate a depres- 

 sion in the raphe and in the plane of the valve. The connecting zone is distinguished 

 by bearing linear bands, which are decorated in a special manner, being marked by stria? 

 alternating with double files of Granules. 



The specific name has reference to this zonal sculpturing. 



Amphora philippinica, n. sp. (Plate XXVII. fig. 2.) 



Valvis ad dorsum arete sinuato-constrictis, apicibus productis acutis ; linea media 

 recta ad polos vix deorsum inflata ; striis transversis perspicuis punctulatis. In mari 

 Philippinarum. 



An acute constriction also occurs in this bi-lobed species from the Philippine Sea. Its 

 apices are very prolonged, sharp, and slightly bent, and its transverse striae are well defined, 

 granulated, and subradiating. 



By referring to A. Schmidt's Atlas 1 (Plate xxv. fig. 62) it may be observed that the 

 present valve resembles the Amphora coarctata of Grunow, of which no description has 

 been given. The latter, however, possesses capitated apices, and the striae are thin, non- 

 sranulated, and not subradiatins;. 



The specific name has reference to the locality in which it was found. 



Amphora thaitiana, n. sp. (Plate XXVII. fig. 15.) 



Elliptico-oblonga, polis rotundatis ; valvis cymbiformibus, dorso late convexo, ventre 

 inflato, apicibus obtusis ; striis transversis validissimis per sulcos longitudinales interruptis. 

 Ad portum Thaiti. 



This type seems to be akin to the form represented in Plate xxviii. fig. 1 5 of the Atlas 

 of A. Schmidt, which is a novelty if it be not the Amphora egregia of Ehrenberg. The 

 present form, however, may be distinguished by its rounded extremities — in the form 

 represented by Schmidt the ends are roundly truncated — and by the ornamentation of the 

 valves. This consists of continuous costae interrupted by longitudinal lines, while in 

 Schmidt's frustule, and in Amphora crassa of Gregory, 2 which it resembles, the valves are 

 distinguished by continuous costae, and the dorsal areas by numerous longitudinal lines 

 separated by rows of spots or small lines. 



The distinction between the appearance of the extremities, apart from other structural 

 differences, might have been explained by supposing that the frustules had attained 

 different stages of development. 



This new form is very abundant in the rich flora of Tahiti, and its specific name is 

 intended to indicate this fact. 



1 Atlas der Diatomaceenkunde, in Verbindung mit der Herren Grundler, Grunow, Janiseh, Weissflog imd 

 "Witt, herausgegeben von Adolf Schmidt, 1875. See also a reproduction of the above about one-half the 

 linear dimensions of the original, by C. Henry Kain, Camden, N.J., 1884. 



2 Op. cit. p. 52, pi. vi. figs. 94, 94Z>, 94c, and 94tf. 



