SO 



HARDWICKE'S SCIENCE-GOSSIP. 



[April 1, 186S. 



Laconia and Bemis Lake, in New Hamsphire ; 

 Greenwich, in Connecticut ; and Monticello, in New 

 York. 



The following are some of the rarer forms in the 

 Duck Pond and French's Pond material. 



Navicida firma, variety f . Valve with three un- 

 dulations, apices rostrate, the peculiar central blank 

 space small and inconspicuous, striae transverse, 

 delicate. French's Pond (fig. 63, x 500). 



Fig. 63. 



This species, according to Dr. Lewis, resembles 

 Navicida Uitchcockii in its marginal undulations 

 and sharp parallel transverse stria?, but differs 

 essentially in the median line, which in Navicida 

 Hitchcockii is remarkable as having on either side 

 a double line nearly parallel to its course through- 

 out. Never having seen an authentic specimen of 

 Navicida Hitchcockii, I am unable to determine the 

 distinctness of the latter species from the triundulate 

 variety of Navicida firma. 



Navicida elliptica (Kutzing). Valve elliptical, 

 striae distinctly moniliform, about 21 in '001, median 

 line and central nodule distinct. Trench's Pond. 

 This species seems to be universally distributed, 

 and is more or less plentiful in most of the North 

 American deposits. 



Pinnularia polyoma (De Brcbisson), variety /3. 

 Valve narrow, linear, with central and terminal 

 inflations, costtu marginal, 21 in '001'. French's 

 Pond (fig. 01, x 400). The form found in this 

 deposit differs from that found by M. De Brebis- 

 son and Dr. Lewis (outline, fig. 05) ; the centre 

 and apices are suddenly and equally inflated, 

 and the margin between the inflations straight ; 



the typical form is undulate, with a large central 

 inflation.* 



Pinnularia cardinalis (Ehr.), variety (3. Valve 

 linear, extremities rounded, costac slightly radiant, 

 about 21 in '001", absent from centre of valve. 

 French's Pond (fig. 00, x 400). It is with hesitation 

 that I place this form with Pinnularia cardinalis, 

 differing as it does in size (the largest valve I have 

 seen scarcely exceeds a quarter the size of the 

 true Pinnularia cardinalis) and closeness of the 

 costse— differences which do not, however, warrant 

 making it a new species. 



a 



C 



Fig. 6/ - . 



Fig-. 68. 



Pinnularia nodosa (Smith). Valve with three, 

 more or less, distinct inflations, extremities subcapi- 

 tate, produced, striae marginal, 18 in '001". French's 

 Pond (fig. 0,7 a b, x 300). This pretty little form is 

 common in the American deposits, but variable in out- 

 line and length. It is the Navicida nodosa of Kut- 

 zing and Gregory (Mic. Joum., vol. iv., pi. 1, fig. 5). 



Stauroneis Stodderi. (Greenleaf) F. V. Linear, 

 with slightly rounded ends. Valve elliptic lanceo-. 

 late, or lanceolate, apices more or less produced, 

 stauros linear reaching the margin, longitudinal 

 striae distinct, about 30 in '001", transverse, slightly 

 radiant, about 55 in '001" (fig. OS, x 500). French's 

 Pond; very scarce in Duck Pond. This very 

 beautiful form is named after Mr. Stodder, ils 

 discoverer, by Mr. Greenleaf, of Boston, U.S. 

 Dr. Lewis, who describes it, says, " The valves are 

 singularly light and graceful, the linear striation 

 giving the surface much the aspect of a Lepisma 

 scale. When the valve is examined by the aid of 

 oblique light (the valve at right angles to the light), 

 the longitudinal striae appear to cross the stauros. 

 "When the valve is placed at an angle of 45°, both 

 longitudinal and transverse striation are seen (fig. 



* The form described by Dr. Gregory in Micrdkcopical 

 Journal, vol. ii., under the name of Pinnularia undulata, is 

 not the Pinnularia Poly onea of De Brebisson; the latter has 

 never been found in Great Britain. 



