SYSTEMATIC ACCOUNT 275 



the valve surface. Angles of valves furnished with large rounded or oval ocelli. Valve 

 mantle deep, constricted just above the girdle zone. Beyond the constriction the valve 

 is usually hyaline. Areoles upon the valve mantle usually larger than on the central area 

 of the valve and somewhat rectangular in shape. Girdle large, furnished with a few 

 irregular lines of small puncta, puncta rounded. Valve mantle slightly recurved after 

 the constriction, as it meets the girdle. Pervalvar axis often greater than the diameter 

 of the valve. Chromatophores : numerous oval plates. Diameter of valve 70-120/x; 

 pervalvar axis mostly 100/x. 



A neritic species, often epiphytic upon larger algae. The frustules attach themselves 

 to the substratum by means of short mucous stipes or flat pads, exuded at the angles of 

 the valve. The species has a wide distribution in temperate seas, and is common around 

 European coasts, particularly upon the Atlantic side. It was observed at one station 

 only in the Peru Current. 



Observed at St. WS 629. 



Biddulphia astrolabensis Hendey, sp.nov. (PI. IX, figs. 1, 2, 3.) 



FrustuMs e facie connectivali visis rectangularibus ; cingulis latis, simplicibus; valvis 

 triangularibus, superficie plana, marginibus rectis vel subarcuatis; costis brevibus, 

 2 vel 3 utroque latere; angulis subacutis, lenissime productis, stromatophoris, stro- 

 matibus parvis, subtiliter punctatis ; punctis minutis, subpinnulatis, sparse irregulariter- 

 que dispositis, in medio paucioribus. 



Mensura valvarum 145/* inter angulos. 



Hob. in aquis marinis " Bransfield Strait", prope insulam "Astrolabe" dictam, in 

 mari Antarctica. 



Typus in Herb. Mus. Brit. No. 33964. 



A meroplanktonic species observed only in small numbers in the material from the 

 Bransfield Strait where the net had touched bottom. The frustules were of extreme 

 fragility, and only after making repeated attempts could a satisfactory mount be made. 

 All the specimens were either dead or in a dying condition when the sample was taken, 

 so no information was obtained concerning the photosynthetic elements. The structure 

 of the valve indicated relationship with the primitive forms of the genus Triceratium, 

 particularly those found in fossil deposits in central Europe, and quite unrelated to the 

 progressive forms of cornutate neritic species, commonly found in the plankton of the 

 southern seas. 



Observed at St. WS481. 



Biddulphia aurita var. obtusa (Kutzing) Hustedt. 



Hustedt, 1930, p. 848, fig. 502. 



Biddulphia obtusa (Kutzing) Ralfs ex Pritchard, 1861, p. 848. 



Odontella obtusa Kutzing, 1844, p. 137. 



Biddulphia par allela Castracane, 1886, p. 103. 



Cells in girdle view oblong, in valve view bipolar, oval-lanceolate to elliptic-lanceolate. 

 Pervalvar axis usually greater than the apical axis. Apices of the valve produced to form 



