56 NEW YORK STATE MUSEUM 



genotypes of E'ugastereila and Encrinaster to such an extent that 

 it seems to serve the purposes of taxonomy best to keep the two 

 groups of species distinct. These new species are Eugaster- 

 ella bicatenulata and E . a r a n e a . As a group they 

 may be said to differ from typical Encrinaster in lacking the dis- 

 tinct petaloid form of the rays, these being much more slender and 

 relatively longer ; and also to lack the marginal plates of the disk. 

 E . aranea forms the extreme of the series of species. In it 

 the ambulacral ossicles, as seen from the abactinal side, are rela- 

 tively long prismatic plates. Since these ossicles, as well as the 

 semiprismatic adambulacrals, are elongate and relatively high, the 

 arms are not broad and flat as in Encrinaster, but narrow and of 

 semicircular section and become whiplike toward the end. 



Eugasterella bicatenulata nov. 



Plate 14, figure 5; plate 16, figures 5-7 



The Grimes sandstone (Portage group) near Naples, N. Y., has 

 furnished beautifully sharp molds of the actinal side of a starfish 

 that proves to be a Portage representative of the interesting genus 

 Eugasterella. 



Description. Starfish of medium size. Disk relatively large 

 (r = 1 1.5 mm); with concave margins; rays slender, slightly 

 petaloid, about 36 mm long and 4 mm at the widest part, which is 

 at about one-third of its length. 



The ambulacrum is wide, with a slightly zigzag-shaped ambu- 

 lacral gutter. The ambulacral plates, as seen from the actinal 

 side, are boot-shaped with a very thick, short " foot " and a dis- 

 tinct "heel.'' The adambulacralia, in their ventrally projecting 

 part, are thick and very high, rising much above the floor of the 

 ambulacrum. They are but slightly curved and extend with their 

 sharply truncated outer extremities beyond the next ossicles, thus 

 forming a distinctly offset series. The proximal end bends hook- 

 like down to the contact with the ambulacral. The projecting 

 truncated distal extremity bears a spine. There are about thirty 

 ambulacrals in a ray and ten in the space of 10 mm. The abactinal 

 side is not now known. 



The syngnaths are small, sharply V-shaped and attached to the 

 adambulacral column. The disk is covered with small irregular 

 plates embedded in the granulose integument. 



