18 THE VOYAGE OF H.M.S. CHALLENGER. 



elongated sublinear form, its centre is slightly inflated, and its extremities are roundly 

 truncated. The continuous stria? form subradiating bars, and are easily discerned. The 

 valves are slightly depressed at the centre. 



It has been named in honour of the Italian naturalist Professor Giuseppe Meneo-hini, 

 one of the earliest cultivators of the study of the Diatornaceae. 



Amphora scalaris, n. sp. (Plate XXVII. fig. 19.) 



Oblonga, truncata, lineis dorsali et ventrali late biarcuatis, centrali medio angulariter 

 inflexa ; striis continuis raris transverse parallelis. Ad portum Jackson in Australia. 



Of this remarkable form, which was collected at Port Jackson, Australia, only a single 

 valve was observed. In this the dorsal line, like the ventral profile, is singularly biarcuate, 

 while the raphe is angularly folded at the centre. The widely separated, transverse, equi- 

 distant, and continuous striae are especially characteristic. The extremities are roundly 

 truncated. 



The specific name has been suggested by the appearance of the transverse striae. 



Amphora polyzonata, n. sp. (Plate XXVII. fig. 18.) 



Forma lata, medio angulariter constricta ; apicibus late rotundatis, truncatis : valvis 

 introrsum inflexis ; zona connectiva in plures fascias divisa ; zona et valvis quadrato 

 ordine punctulatis. Ad portum Thaiti. 



In this species from Tahiti, just as in some Naviculce, well-marked constrictions occur. 

 Thus the valval involution is so strong and acute as to simulate the staurotic dilatation 

 of a central nodule. A strongly biarcuated line forms a raphe, and the frustule, which 

 is twice as long as broad, is widely and roundly truncated at the extremities. The con- 

 necting zone bears several longitudinal bands which, like the valves, have the granules 

 arranged in a quadrate manner. 



Plate XXVII. fig. 8, represents a two-lobed form which is angularly constricted, but 

 far less deeply than Amphora polyzonata. The raphe is also strongly biarcuate, but the 

 extremities are round and non-truncated. The length of the frustule is more than twice 

 its breadth. The connecting zone bears longitudinal bands which, like the valves, are 

 punctated. It may therefore be regarded as a mere variety of the former, the distinctions 

 indicated being such as might result from differences in development. It was obtained 

 at the port of Tahiti. 



Amphora decora, n. sp. (Plate XXVII. fig. 14.) 



Late inflata, elongata ; apicibus obtusis subproductis ; valvis medio inflexis ; zona 

 connectenti in fascias divisa, binis granulorum ordinibus et striis alternis insignita. Ad 

 mare Philippinarum. 



This beautiful little Amphora, from the mud of the Philippine Seas, has a widely 

 inflated profile, and obtuse, slightly prolonged extremities. Each of the two valves, 



