. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. ECH1N0IDEA. II. IOy. thodique. p 41), who limits the genus to include only the species in which the posterior ocular plates are not separated by the madreporite. Considering, however, what has been made known by Gauthier about the apical system in some species of Hemiaster (< )p. , I would not feel inclined to separate the P. limicola from the genus Periaster on this account. (Comix also De Loriol. Notes pour servir a l'etude des Echinodermes. VI. p. 175 and Lambert. Note sur le deve- loppement de l'Echinospatagus ne
. The Danish Ingolf-Expedition. Scientific expeditions; Arctic Ocean. ECH1N0IDEA. II. IOy. thodique. p 41), who limits the genus to include only the species in which the posterior ocular plates are not separated by the madreporite. Considering, however, what has been made known by Gauthier about the apical system in some species of Hemiaster (< )p. , I would not feel inclined to separate the P. limicola from the genus Periaster on this account. (Comix also De Loriol. Notes pour servir a l'etude des Echinodermes. VI. p. 175 and Lambert. Note sur le deve- loppement de l'Echinospatagus neocomiensis. p. n. Note). The labrum reaches the beginning of the second adjoining ambulacral plates. The actinal plates of the posterior ambulacra are rather elongate; the first of the 5 large subanal tube-feet is found on the 5th ambulacral plate. The frontal tube-feet have a well developed disk, with numerous elongated, narrow rosette-plates; the edge of the disk is not lobed. The spicules are irregular, slightly branched rods. Long genital papillae occur. Globiferous tridentate, rostrate and triphyllous pedicellaria; have been found. The , , ., .. ,. „ „-.,- _. , , , Fig. 21. Apical system of Periaster globiferous pedicellaria; (PI. XIV. Figs. 6, 9) have a rather large (glandular) limicola. h ,. space within the blade, continuing almost to the articular surface; the terminal opening has two teeth on either side. The stalk has a thickening above and below, but no free, projecting rods. — (July one small rostrate pedicellaria was found, which does not show any peculiar feature. The tridentate pedicellaria; occur in two, not very distinct forms: one (PL XIV. Fig. 35) with the blade somewhat widened in about the outer third part, where the valves join, the edge of this widened part being finely serrate, that of the lower part smooth; the other (PI. XIV. Figs. 28,44,47) with the blade very elongated, slender, narrowing evenly towards the basal part, the edge being serrate i
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