20 



JAMES A. GRIEG 



[REP. OF THE "MICHAEL SARS" NOHRT 



extreme point of the arm, frequently only two more or less 

 distinct rows of papillae, the hindmost of which equal 

 in size the granules of the adjoining ventro-lateral plates. 

 The number of papillae varies in the furrow row as well 

 as in those behind it, as will be clearly seen from the 

 following account of the number of papillae in 7 successive 

 adambulacral plates of the inner half of the arm of the 

 largest specimen: 6 — 2 — 4 — 3, 5 — 3 — 2 — 3, 5 — 3 — 3 — 4. 

 5—4—3—4, 6—4—4—3, 7—4—5—4 and 6—3—5—5. 

 Dorigona arenata occurs on both sides of the North 

 Atlantic. It was first found by the "Blake" off the West 

 Indies between Grenada (12° N) and 24° 36' N., at 298- 

 1748 m, where it was later also taken by the "Albatross" 

 On the east Atlantic side it was first taken by the 

 "Challenger" southwest of the Canary Is. at 2791 m. 

 The "Travailleur" and the "Talisman" took it later at 

 16 stations between the Canary Is. and the Bay of 

 Biscay (44° 4' - 29° 1' N, 407 - - 1805 m.) and there 

 it was also found by the Prince of Monaco at 40 stations 

 between 29 c 6' and 47° 45' N., 1096 1588 m. 



The "Caudan" obtained it at three stations in the Bay 

 of Biscay, 400 - - 1410 m. It is finally recorded under 

 the names of Nymphaster protentus, N. subspinosus and 

 N. arenatus from the great depths west of Ireland, 381 — 

 1332 m. Dorigona arenata thus ranges on the west 

 Atlantic side from 12 : to 24° 36' N., and on the east 

 Atlantic side from 25° 45' to 51° 23' N. The 

 bathymetrical distribution is 298 to 2791 m. 



Para.gona.ster subtilis Ed. Perrier. 

 Goniopecten subtilis Ed. Perrier, Bui. A1us. Comp. Zool. vol.9, 1881. 



p. 26. 

 ,9 /4. Stat. 10, 4.5° 26' N., 9° 20' W., 4700 m., yellow sand, 

 temp. 2.56° Cel. Two large unfortunately defective, specimens and a 

 very young one. The disc-radius of the two former was 19.5 mm. 

 and 15 mm. respectively. The small specimen measured: 



Arm-radius 10 mm. 



Disc-radius 4 „ 



r : R 1 : 2.5 



Number of dorso-marginal plates 7-8 



Number of ventro-marginal plates 8 — 9 



The small specimen differs from the two fully deve- 

 loped ones in having the dorso-marginal plates more 

 scantily covered with granules, which form a marginal 

 border; for the rest granules are absent or a few scattered 

 ones only occur. In the two large specimen on the other 

 hand the plates are completely covered with granules. 

 In like manner the ventro-marginal as well as the abactinal 

 plates of the small specimen present more scanty granu- 

 lation. The terminal plates end in two spines which 

 are turned forward, are comparatively broadly and straightly 

 cut off and among which 2 to 4 more spines of smaller 

 and more slender dimensions are found. 



The adambulacral plates of the two large specimens 

 carry 4 - - 8 furrow papillae, most frequently 5 to 6, and 

 behind them 12 papillae arranged in three distinct rows. 

 Pedicellariae were absent in both specimens. 



Paragonasler subtilis is evidently identical with P. 

 strictus Perrier, which I can not but consider as the 

 juvenile form of this species as was also indicated by 

 Perrier 1 ). I agree with Koehler 2 ) in further referring P. 

 elongatus Perrier 3 ) to the same species and likewise P. 

 cylindratus Sladen 4 ), which was found by the "Challenger" 

 south of the Cape Verd Is. (1° 47' N. 24° 26' W., 3386 m., 

 temp. 2.6° Cel.) 



Verrill 3 ) remarks about the relation between P. cylin- 

 dratus Sladen and P. formosus Verrill, taken of the east 

 coast of the North America between 37° and 41° T N., 

 at 2455 to 3698 m., that the latter "appears to have the 

 adambulacral plates more salient and angular on the 

 furrow-margin and the notches between them deeper; 

 the furrow-spines appear to be more slender and form 

 a more strongly curved or angular group, which is conti- 

 nued by three to five shorter ones in a fasciole-like row 

 on the proximal and distal edges of the plates; there are 

 about five on the furrow-edge proper; the spines on the 

 actinal surface are more elongated and more regularly 

 stellated, with a longer one in the middle of the group. 

 — The spinules of the lower marginal plates have the 

 same arrangements as in Sladen's species, but are slightly 

 more slender and acute than shown in his figure; of 

 the larger median series there are usually two or three 

 irregular indefinite rows in the larger specimens, instead 

 of a single definite row. These differences are, however, 

 so slight that the two former may prove to be the same 

 species". 



One of the two larger specimens mentioned by me 

 is a typical Paragonaster subtilis, the other agrees more 

 closely with Verrill's form, which according to him I must 

 regard as identical with P. cylindratus, and consequently 

 also with P. subtilis, the type specimen of which was 

 taken by the "Blake" off the Antilles (24° 33' N., 84° 23' W„ 

 3532 m.) 



Paragonaster subtilis must therefore be a North 

 Atlantic species ranging on the American side from 24° 33' 

 to 41° T N., 2455—3698 m., and on the European side 



') Ed. Perrier: Echinodermes, Exp. Sci. du "Travailleur" et du 

 "Talisman", 1894, pag 363, tab. 24, fig. 7, tab. 25. fig. 5. 



2 ) Koehler: Echinodermes, Res. Camp. Sci. Monaco, Fasc. 34, 1909, 

 p, 86, tab. 4, fig. 2. 



3 ) Ann. Sci., Nat., ser. 6, Zool. tome 19, 1885, no. 8, p. 38. 



4 ) Sladen: Challenger Asteroidea, p. 314, tab. 51, figs. 3 & 4, 

 tab. 53, figs. 3 & 4. 



'-) Proc. U. S. Nat. Museum, vol. 17, 1894, p. 257. 



