CONOLAMPAS. 117 



sinuate and more or less incurved. Between the smallest and largest forms, 

 numerous intermediates are found, their margins (PI. 144, fig. 23) showing more 

 or less marked sinuations. 



This is beyond doubt the best defined species in the genus. The small size 

 and inequality of the poriferous areas, the sparse tuberculation, and the remark- 

 able tridentate pedicellariae form a notable combination of characters. In 

 the poriferous areas and in the shape of the test it is nearest depressa, but the 

 tuberculation and pedicellariae are quite different and the periproct is not so 

 distinctly oral in position as in that species. The Albatross took two specimens 

 of sternopetala during its trip to Japan in 1900 and secured another (the holo- 

 type) during the voyage of 1906. 



Station 3749. Off Suno Saki, Honshu Island, Japan. Bott. temp.? 83- 

 158 fms. Bk. s., sh. 



Station 4934. Off Kagoshima Gulf, Japan. Bott. temp. 60.6°-56°. 

 103-152 fms. St., rky. 



Bathymetrical range, 83-158 fms. 



Three specimens. 



Conolampas. 



A. Agassiz, 1883. Blake Ech., p. 48. 

 Type, Conoclypus sigsbei A. Agassiz, 1878. Bull. M. C. Z., 5, p. 190. 



Plate 144, figs. 25-32. 



The validity of this genus has been called in question but examination 

 of the pedicellariae and spicules confirm the opinion that it is a well-marked, 

 natural group. The almost circular ambitus, the five identical ambulacra, the 

 equality of the poriferous areas extending to the ambitus, the conspicuous 

 phyllodes and bourrelets about the central peristome, and the sharp angle formed 

 by the oral surface and the sides of the test, which are nearly vertical at the 

 ambitus, form a really significant combination of features. And to these may 

 now be added a noteworthy arrangement of the plates around the peristome. 

 Jackson (1912. Phylogeny Ech., p. 72) has pointed out that in Lovenia forbesi 

 from the Australian Miocene, the primordial plates in interambulacra 1 and 

 4 are pushed out from the basicoronal row dorsally, so that the primordial 

 ambulacrals 16 and Ila, and IV6 and Va are in contact. In several spatangoid 

 genera, besides Lovenia, interambulacra 1 and 4 are thus shut out (see pis. 148, 

 fig. 8; 150, fig. 5; 151, fig. 7; 152, fig. 3). This same condition exists in 



