218 Transactions of the 



II. — New Diatoms. By F. Kitton, Norwich. 



{Read ln-fore the Royal Miceoscopical Society, October 7, 1874.) 



Plates LXXXI. and LXXXII. 



Thkough the kindness of my friend Captain Perry, of Liverpool, 

 I am enabled to introduce to the notice of the Fellows of this 

 Society some new and rare forms of Diatomacese which I have 

 detected in a dredging made by him off Navy Bay, Colon, Panama. 



This gathering is one of the most interesting it has ever been 

 my fortune to examine : in addition to the many fine forms of 

 Diatomaceae, Foraminifera and Polycystina are not of unfrequeut 

 occurrence. Silicified casts of the borings of some species of Cliona, 

 the chambers of Foraminifera (often with the pseudopodal apertures), 

 fragments of Ecliinus spines, and Bryozoa may be found among 

 the heavier debris after the calcareous matter has been destroyed by 

 acids. 



The species of Diatomaceae are numerous and fine ; those which 

 I am about to describe are, I believe, new. 



Perrya, N. Gr., mihi. 



Free, elongated, frustules compressed, sometimes slightly con- 

 stricted, extremities rounded, striae transverse moniliform. Marine. 



This genus is distinguished from Nitzschia, its nearest ally, by 

 the absence of a keel, and also by its very much compressed valve. 



P. pulcherrima, F. K. — Valve in f. v. linear, inner or ventral 

 margin straight or very slightly concave, outer or dorsal margin 

 straight, suddenly rounded at the apices, markings, distant monili- 

 form dots, in transverse series, not reaching ventral margin, between 

 which are fine moniliform striae, s. v. narrow, linear, suddenly taper- 

 ing towards the acute extremities, a central line of large moniliform 

 dots dividing the valve. Length • 0090" to • 0200", breadth • 0015". 

 Navy Bay, Colon, Panama ; Campeche Bay. = Nitzschia imlcher- 

 rima Grrunow, m. s. Herr Weissfiog, in litt. PI. LXXXI., Fig. 1, 

 valve f. V. ; 2, frustule ; 3, ideal section of ditto. 



This form somewhat resembles Nitzschia, but the compressed 

 valve and absence of keel indicate that the resemblance is only 



DESCRIPTION OF PLATES LXXXI. AND LXXXII. 



Fig. 1. — Perrya jyulchcrrimx, valve. 

 „ 2. — „ „ frustule. 



„ 3 — „ ,, ideal section of ditto. 



„ 4. — Surirella contorta, valve. 

 ,, 5. — Nitzschia grandis. 

 „ 6. — „ „ outline of frustule. 



,, 7. — Tricerntiiim fitvus, var. yc2it-itnijulatutn. 

 „ 8. — Portion of inner surface showing the punctate film. 

 All X 400 diameters. 



