REPOKT ON THE DIATOMACE^E. 21 



canal of Trail, Dalmatia, for the purpose of studying the flora of the Adriatic. In 

 this locality a perfect Cymbella was observed, in a preparation fresh from the sea, in 

 a moving condition. Species have also been recorded in sand obtained by Gwyn Jeffreys, 

 the well-known conchologist, in the vicinity of the Shetland Islands, although Professor 

 Dickie, who first studied these gatherings, believed that the cymbelloid frustules were 

 deposited on the bottom, after having been carried into the sea by rivers. 



Cymbella criophila, n. sp. (Plate XXVII. fig. 5.) 



Porma marina (?) elongata, sensim ad acutissimos apices declinans ; linea dorsali con- 

 vexa, ventrali vix convexiuscula ; striis perspicuis punctulatis subradiantibus, ad centrum 

 lineani mediam bine inde insequaliter non attingentibus. Ad meridiem insulae Heard. 



This interesting species, which was obtained to the south of Heard Island, has an 

 extremely convex dorsal line, the ventral being only slightly convex. The frustule tapers 

 at each end to a very sharp point. The striae are well marked, and subradiating in 

 disposition, each being formed by a series of very minute points. Those towards the 

 middle of the frustule do not meet in the centre, where a smooth area which is notably 

 larger on the more convex than on the less convex side of the valve is to be found. 



This Antarctic Diatom may have been transported by icebergs into the sea, although 

 the probability that it is truly marine must be borne in mind. 



Cymbella marina, n. sp. (Plate XXVII. fig. 13.) 



Forma marina, elongata ; linea ventrali recta, dorsali late arcuata ; apicibus rotundato- 

 acutis ; striis transversis parallelis, lineam mediam non attingentibus. Ad mare Japonicum, 

 prope Yedo. 



This species was obtained near Yedo in the Sea of Japan. The ventral line is straight, 

 and the apices are rotundately acute. The valval striae are parallel and terminate near 

 the raphe, a non-striated nodule being left in the centre and being especially prominent on 

 the side next the dorsal line. 



That this form is truly marine cannot be questioned. 



Cymbella pelagica, n. sp. (Plate XXVII. fig. 4.) 



Mediocris ; dorso turgido, ventre leniter convexo ; linea media subcurvata ; apicibus 

 obtuso-truncatis, productis ; striis moniliformibus subradiantibus. 



The dorsal line, in this form, is greatly arcuate, the ventral being slightly convex. 

 The apices are obtuse and somewhat prolonged, and the raphe is slightly curved. The 

 striae are subradiating and moniliform. 



This Diatom, like the preceding, must be looked upon as a truly marine form, inas- 

 much as it has been observed in a moving condition under the microscope, and has been 

 met with in more than one collection from the sea. 



