. Echinoidea. Sea urchins. 74 ECHINOIDEA. II. pnshed far backwards, separated from the small inner plate at tlie peristome not onh- bv the ambn- lacral piates I\. h. 2—4 and II. a. 2—3, the posterior one of theni being much prolonged backwards along the ainbiilacral piates and I. b. I, bnt also bj'the interarabulacral plates4. a. 4 and 4—5, whichjoin the ambulacral piates V. a. 1 — 2 and I. b. I — 2 for a long way. The piates I. a. 4 and 4. b. 4 are very mnch en- larged, and upon the whole all the piates of these interambnlacra are nnnsnally large. As in pliinlc these interambnlacra
. Echinoidea. Sea urchins. 74 ECHINOIDEA. II. pnshed far backwards, separated from the small inner plate at tlie peristome not onh- bv the ambn- lacral piates I\. h. 2—4 and II. a. 2—3, the posterior one of theni being much prolonged backwards along the ainbiilacral piates and I. b. I, bnt also bj'the interarabulacral plates4. a. 4 and 4—5, whichjoin the ambulacral piates V. a. 1 — 2 and I. b. I — 2 for a long way. The piates I. a. 4 and 4. b. 4 are very mnch en- larged, and upon the whole all the piates of these interambnlacra are nnnsnally large. As in pliinlc these interambnlacra are ver\- mnch bent npon themselves, the median part being near the posterior end, where- as the tipper and lower end is at the anterior end of the animal. That the interpretation of the piates given here is correct seems beyond donbt, from a comparison with P. phiale (Fig. 10), in which the interpretation lies qnite evident. — The piates of the antero-lateral ambulacra and in- terambnlacra are rather small, in accordance with the small size of the - line there. Also the small innerinost plate of the antero-lateral. (Sternum). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Mortensen, Th. (Theodor), 1868-1952. Copenhagen, Printed by Bianco Luno
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1900, bookyear1903
