Research Notes New Zealand Fossil Asterozoa 3. Odontaster priscus sp. nov. from the Jurassic By H. Barraclough Fell Victoria University College, Wellington, New Zealand [Read before Wellington Branch, April 28, 1954; received by Editor, March 29, 1954.] Abstract Odontaster priscus sp. nov. is described from a Temaikan horizon (Bajocian-Bathonian) near Onewhero, South Auckland. The genenric determination is based on a ambulacral peculiarities which are considered to be diagnostic of Odontaster sensu lato. Order Phanerozonia Family Odontasteridae Genus Odontaster Verrill 1880 Type species Odontaster hispidus Veirill Odontaster prisons sp. nov. Holotype (Figs. 1 and 2)—an internal negative mould in medium sandstone of the coelomic surface of the adoral body-wall. It was collected by Miss Helen McKenzie from Moewaka Quarry, Opuatia Stream, Onewhero Survey District, Geological Survey locality G.S. 5037, and through the courtesy of Dr. C. R. Laws is now in the N.Z. Geological Survey collection, specimen EC. 184. Marwick (1953. p. 126) considers the horizon to be Temaikan, about Bajocian or Bathonian. Of small size, R estimated to be 11.0 mm., r about 3.5 mm. Disc evidently stellate. tapering evenly into the arms Distal parts of arms lacking, but apparently acuminate. A ring of five pair of large, elliptical skeletal plates surrounds the mouth, one pair at the proximal end of each ambulacral series. Each plate is about 1 mm. in length, with the major axis directed radially, and the better preserved ones have the upper surface concavely excavate and traversed by three or four transverse ridges. The relationship of these structures to one another and to the ambulacral series and to the mouth can best be under stood by refer-once to Fig. 2. which is to be treated as the essential diagnosis of the species. Discussion Until the discovery in August. 1952. of this problematic fossil no Jurassic asteroid was know from New Zealand. Although identification appeared at first sight almost hopeless, the unusual character of the five pairs of radially-placed ridged plates around the mouth seemed to offer a chance of success. It was first assumed that the mould was a negative impression of the adoral lower surface, and that the grooved plates were therefore oral plates. A few genera, such as Archaster, have very large oral plates, but their detailed sculpture differs, and it was difficult to understand why the plates in the fossil were grouped in radial pairs instead of interradial pais, as is universally the case Furthermore, the lack of any impression of inferomarginals was puzzling, and seemed to point rather to some non-phanerozonian genus, in which case the large size of the oral plates seemed anomalous. The alternative interpretation was therefore tired, namely that the specimen is a negative impression of the internal adoral surface, such as would result from the percolation of sand and mud into the coelomic cavity after decay of the aboral surface of the disc. On this assumption the grooved plates would be some peculiar development of the ambulacral series of ossicles This would account for their radial position and for their relatively greater distance from the month impression than should be the case with oral plates. It would also explain the lack of any impress of marginal plates. Since internal skeletal structures of asteroids are seldom mentioned in.