10 GREVJI.LE, ON DIATOM ACEyE. 



theless tlie resemblance is so perfect, that, if it were possible, 

 they might pass for the reflection of real windoAvs. The 

 figure cannot give the effect of this, as the transparency of 

 the valve is necessary to complete the deception. 



5. Campylodiscus Ecclesianus, Grev. Valve nearly circular^ 

 the border composed of a double series of narrow-oblong cells ; 

 disc with two rows of short, broad, truncated bars, separated by 

 a broad median line, from each end of which radiate a semi- 

 circle of fine striie. Diameter of frustule 0- 0024", (PI. Ill, 



Of this fine species, not less charming in the elegance of 

 its sculpture than the preceding, the gathering furnished 

 two examples. It is similar in size to the last, but some- 

 what more contorted, so that, when one portion of the valve 

 is in focus, the details of the remaining portion are less visible 

 than as they are represented in the figure. The valve is very 

 concave. The central part of the disc occupied by the two 

 rows of bars is nearly flat ; but on each side of the rows and 

 at their termination the disc is inflated ; the lateral inflations 

 being unsculptured, the terminal ones ornamented with striae, 

 which radiate from the ends of the median line, and stop 

 before reaching the border, so as to form a semicircle. I am 

 not aware of any known species which can be brought into 

 comparison with this splendid form, on which I have conferred 

 the name of Mrs. William Eccles, a lady who has most kindly 

 collected for her friends many objects of natural history in 

 the Island of Trinidad. 



6. Surirella eximia, Grev. Valve linear-oblong, rounded at 

 the ends, very slightly constricted in the centre; canaliculi 

 delicate, about 18 on each side, reaching the narrow-linear, 

 transversely striated median line, which is attenuated towards 

 the ends, and becomes as narrow as the canaliculi. Length 

 of frustule 0-0020" to 0-0028"; breadth 0-0008" to 0-0012". 

 (PL III, fig. 6.) 



This extremely delicate and hyaline Diatom aj)proaches S. 

 lata in form, but differs in every other respect. The cana- 

 liculi are equidistant, and as fine as those of S. (jemma ; the 

 aire narrow, but conspicuous. A characteristic feature is the 

 linear, transversely striated median line, which is gradually 

 attenuated at each extremity, until at about the third or 

 fourth pair of canaliculi from the end it becomes as slender 

 as the canaliculi themselves. 



7. Navicula Grcfforiana, Grev. Valve elliptical-oblong, 

 with abruptly produced and roimded ends ; strife obscurely 

 moniliform, interrupted on each side by a longitudinal, linear, 

 blank space, which slightly converges towards tlve central 



