164 



Bulletin, Vanderbilt Marine Museum, Vol. IV 



wall is thick, the scales rather small, immersed in the skin, granulated. 

 The grains on the scales are globular, about 0.3 mm. diameter. The 

 deposits of the ventral sole are of two kinds: small cups and larger 

 spherical, oval bodies of a perforated, somewhat complicated structure. 

 The tube-feet are arranged in three irregular rows, those in the mid- 

 radius in a complete series in the whole length of the sole. The two 

 dorsal retractor muscles are attached to the body-wall in the inter- 

 radii, a character which establishes a very constant distinction between 



Text fig. 11. — Psolus phantapus (Strussenfelt), typical calcareous bodies from 

 the skin, greatly magnified. (After Mortensen.) 



this species and P. squamatus in the younger stages where they 



closely resemble one another. 



References: Holothuria phantapus Strussenfeldt, Vet. Akad. 

 Handlg., vol. XXVI, pi. 10, p. 263, 1765. 



Psolus phantapus Jager, de Hoi., p. 21, 1833. — Forbes, British Star- 

 fishes, p. 203, 1841. — Stimpson, Proc. Boston Soc. Nat. Hist., IV, 

 p. 67, 1851. — Verrill, A. E., Proc. Boston Soc. Nat. Hist., vol. X, 

 p. 353, 1866, Bull. Essex Inst., vol. Ill, p. 5, 1871.— Ganong, W. F., 

 Bull. Nat. Hist. Soc. New Brunswick, no. VI, p. 56, 1887.— Bell, 

 F. J., Cat. Brit. Echinod. Brit. Mus., p. 44, 1892 (with extensive 

 synonymy) . — A. H. Clark, Kept. Canadian Arctic Exped., 1913-18, 

 vol. VIII, part C, Echinoderms, p. lie, 1920. — Mortensen, Dan- 

 marks Fauna, Echinod., p. a40, figs. 119, 120, 1924; Handbook 

 Echinod. British Isles, p. 415, fig. 251, 1927. 



Psolus laevigatus Ayres, W. O., Proc. Boston Soc. Nat. Hist., vol. IV, 

 p. 6, 1851. 



