508 PROFESSOR GREGORY ON 
these plates in four species, all of which have the general aspect of Amphiprore, 
naturally leads to the inquiry, whether this remarkable structure may not be 
found in all the species of the genus, or whether the forms in which it occurs 
ought not to form a new genus. I understand from Mr Roper, that he has found 
this species in a marine gathering from the coast of Wales, or of the south of 
England. 
62. Amphiprora (?) complexa,n. sp. PI. XIL., figs. 62 ; 62, b; 62,c; 62,d; and 
62,e. Form elliptical, broad, with a constriction in the middle, and broadly rounded 
ends. The frustule is composed of two arcuate and constricted segments, which 
are broad, thick at the outer margin, thin at the inner margin, and placed oppo- 
site each other, with a narrow interval between them. Over the middle of these 
two lateral segments is placed a complex mass, formed of five or six segments, 
converging inwards and on the ends, like the segments of an orange or melon. 
The thick backs of these central segments, marked with transverse strie, are 
alone seen in the entire frustule, and those of the outer segments approach near 
to the outer margins of the lateral or flat lying segments, leaving only part of 
the surface of the latter exposed. A convex line joins the convergent ends of the 
central segments 
When the frustule, as often happens, falls asunder, a number of segments are 
found lying near each other. Some of these have no constriction, and no nodule; 
these I take to be the segments of the central mass. Those with nodules at the 
middle of their outer margin, at the constriction, seem to be the lateral seg- 
ments. é 
Length of frustule 0:0035" to 0-004’ ; breadth 0:0028’. Segments arcuate, broad ; 
some with a nodule and constriction on the thick convex or outer margin, others 
without. Surface of segments finely striated; striae about 45 in 0:01, delicate, 
radiating from the thin or inner margin, and curved near the ends of the segment. 
At the margin, there is a row of conspicuous puncta, about 1 for every 2 striz. 
The backs of the central segments, when im situ, are striated, but exhibit neither 
nodule nor puncta. 
It is with much doubt that I refer this very curious form to Amphiprora; 
which I should not do, were it not that the lateral plates in four species already 
described may be regarded as the rudiments of the complex central mass in 
this species. One of the three alluded to, Ap. plicata, has even longitudinal folds 
in the middle part. 
It is, however probable, that the remarkable structure of this species may 
render necessary the establishment of a new genus, a step which I do not venture 
to take without farther inquiry. 
This form, like the preceding one, first caught my eye in the Glenshira Sand, 
where I could find, however, only detached segments, and one half frustule. Not 
being able, from these, to understand the structure, and not, indeed, perceiving the 
