70 



ECHINOIDEA. I. 



St. 69. (62° 40' N. Lat, 22° 17' W. L. 589 fms. 'Slud. 3 9 bottoin temp.). i specimen. 



- 73. (62° 58' - 2f 28' - 486 - _ 5^' I - ). 3 _ 



- 76. (60° 50' — 26° 50' — 806 -- — 3^ 7 — ). I — 



- 83. (62° 25' - 28° 30' - 912 - ? 3^ I - )• 3 . - 



From previous collections we have some specimens from tlie Davis Strait (66° 49' N. Lat., 

 56° 28' W. L. 235 fathoms. Wandel). 



Phormosoma placenta is distributed over the whole northern part of the Atlantic, from the West 

 Indies to the Davis Strait, from the Bay of Biscay to the Faroe Islands and Iceland. It has been 

 taken on depths from 150—1356 fathoms (Bell Catalogne, Hoyle 202, Rathbun 337), but it seems 

 chiefly to be found on ca. 400 — 1000 fathoms. Koehler (226. p. 91) also observes that it is <rélative- 

 ment rare dans les dragages profonds>. It is an archibenthal form scarcely occurring on the great 

 depths in the Atlantic, but limited to the territories of the mentioned depth that stretch across the 

 Atlantic south of Iceland and then foUow the European and American coasts southward. It is scarcely 

 found north of the ridge across the Denmark Strait or that between Iceland and the F'aroe Islands. 

 It seems absolutely to demand a positive bottom temperature. 



6. Calveria hystrix') Wyv. Thomson. 



PI. III. Kigs. 1-2. PI. XI. Figs. 5, 29. PI. XII. Fig. 34. PI. XIII. Figs. 17, 18. PI. XIV. Figs. 13, 26. 

 Synonym: Asthciiosoiiia liystrix (Agassiz, Bell, Koehler etc). 



Non: Calveria (Astheiiosoma) feiiesfrala Wyv. Thomson. 

 Principal literature: Wyv. Thomson: Echinoidea of Porcupine> (395) p. 738. PI. LXIV — LXV. 



— A. Agassiz: Revision of Echini II. p. 273. PI. II. c. Fig. 1—5 (?). — 6 p. 74. — 14 p. 3. PL II. Fig. 1 — 2. 



— W.E. Hoyle: Revised List of Brit. Echinoidea. (202) p. 407. — F. Jeffr. Bell: 72 p. 526. PI. XXIV— 

 XXV. — Catalogne of British Echinoderms. p. 143. — R. Koehler: 229 p. 9. 



After the excellent description of this species by Wyv. Thomson it is unnecessary here to 

 give a new thorough description of it; only a few points stand in need of a somewhat more exact 

 description than has hitherto been given. 



The primary spines on the actinal side are curved (somewhat more than shown by the figure 

 (PL III. Fig. 2)), and end in a small, short, and somewhat widened hoof; it is whitish, and consequently 

 rather conspicuous on the pink spine. Flaring at the extremity >, Agassiz (14 p. 5) says of the spines, 

 otherwise their ending in a hoof is not mentioned in the literature. In transverse sections of the 

 spines (PL XI. Fig. 5) it is seen that the longitudinal ridges are rather low, widened in the outer part, 

 with a little projection (indented) on the outside. The small spines on the abactinal side give in trans- 

 verse sections a figure a little different (PL XI. Fig. 5 b); the outer surface of the longitudinal ridges 

 is finely arcuate, and their edges are almost joining. 



The pedicellariæ have been excellen tly described and figured by Wyv. Thomson, who gives, 

 however, no figures of the single valves, so that the features systematically most important cannot be 

 seen in his figures. In the larger form of tridentate pedicellariæ (PL XIV. Fig. 26) the blade is highly 



I) On PI. III it is wrongly cailed Astlienosoma; this plate was reproduced before my stay at British Museum, that is 

 to say, before I had a quite clear understandiug of the geiieric relations of the Echinothurids. 



