ECHINOIDEA. I. 



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



- 73. (62 58' 23 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 the 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 1501356 fathoms (Bell Catalogue, Hoyle 202, Rathbun 337), but it seems 

 chiefly to be found on ca. 40x3 1000 fathoms. Koehler (226. p. 91) also observes that it is relative- 

 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 follow the European and American coasts southward. It is scarcely 

 found north of the ridge across the Denmark Strait or that between Iceland and the Faroe Islands. 

 It seems absolutely to demand a positive bottom temperature. 



6. Calveria hystrix ') Wy v. Thomson. 



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



Synonym: Asthenosoma hystrix (Agassiz, Bell, Koehler etc.). 

 Non : Calveria (Asthenosoma] fenestrata Wy v. 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. i 5 (?). 6 p. 74. 14 p. 3. PI. II. Fig. i 2. 

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

 XXV. Catalogue of British Echinoderms. p. 143. -- R. Koehler: 229 p. 9. 



After the excellent description of this species by W y v. T h o m s o n 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 actiual side are curved (somewhat more than shown by the figure 

 (PI. 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 (PI. XL 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 (PI. XI. Fig. 5b); the outer surface of the longitudinal ridges 

 is finely arcuate, and their edges are almost joining. 



The pedicellariae have been excellently 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 pedicellariae (PI. XIV. Fig. 26) the blade is highly 



') On PI. Ill it is wrongly called Asthenosoma; this plate was reproduced before my stay at British Museum, that is 

 to say, before I had a quite clear understanding of the generic relations of the Echinothurids. 



