SYSTEMATIC ACCOUNT 269 



in a small indistinct spine. Chromatophores : numerous rounded bodies. Diameter of 

 valve 186-220/x. 



Observed at St. 1584. 



Genus Asteromphalus Ehrenberg 



Ehrenberg, 1844 



Asteromphalus elegans Greville. 



Greville, 1859 b, p. 161, pi. 7, fig. 6. 



Asteromphalus wyvillii Castracane, 1886, p. 134, pi. 5, fig. 6. 



Cells discoid, flat or nearly so. Valves almost circular in outline. Valve surface divided 

 into twelve to twenty-six sectors, by narrow regular rays which proceed from the hyaline 

 central area. Central area large, occupying one-third more or less, of the total diameter 

 of the valve surface. Central area traversed by a system of lines arranged around the 

 sides of the nucleal line. Nucleal line in the form of a loop. Each small line is genu- 

 flexed, sometimes bifurcate and joins the apex of one of the radial sectors. Radial sec- 

 tors regular, somewhat pointed toward the valve centre, or sharply truncated, and 

 covered with fine puncta. Puncta usually larger towards the central area. Chromato- 

 phores: several rounded bodies. Diameter of valve 100-180/x. 



This species was observed at one station only in the Humboldt Current, where it 

 occurred in small numbers. A neritic form, recorded from off the Galapagos Islands 

 by Mann. Type locality: Californian guano. 



Observed at St. WS 630. 



Asteromphalus heptactis (Brebisson) Ralfs ex Pritchard. 



Pritchard, 1861, p. 838, pi. 8, fig. 21. 



Gran 1905, p. 45, fig. 49. 



Hustedt, 1929, p. 494, fig. 277. 



Lebour, 1930, p. 52, fig. 28 a. 



Spatangidium heptactis Brebisson, 1857, p. 296, pi. 3, fig. 2. 



Asterolampra heptactis Greville, i860, p. 122. 



Asteromphalus reticulatus Cleve, 1873, p. 5, pi. 1, fig. 2. 



Asteromphalus ornithopus Karsten, 1905, p. 90, pi. 8, fig. 13. 



Cells discoid, small. Valves slightly convex, undulate, sometimes slightly oval in 

 shape. Hyaline area eccentric, small, usually occupying one-quarter to one-third of the 

 total diameter of the valve surface. Hyaline rays proceed from the central area to the 

 periphery dividing the valve into seven sectors. One ray is usually much narrower and 

 longer than the others, and proceeds from the centre of the hyaline eccentric area. 

 A number of branched lines traverse the hyaline area and are arranged around the longer 

 and narrow ray. Peripheral sectors areolate, areoles coarse, arranged in tangential lines. 

 Areoles usually of uniform size throughout. Sectors not rounded. The hyaline rays 

 terminate at the margin of the valve in a small process. The areolate sectors between 

 the hyaline rays are often depressed. Diameter of valve 64-1 10/x, mostly 72^. 



A very variable species, commonly found in European waters. Frequently met with 

 around South Africa, and in the Peru Current, but seldom in great numbers. 



Observed at Sts. 425, 451, 453, 661, 677, 681, 1356, 1359; WS 550, 705, 706, 707, 709. 



