Holothuroidea from Southern Chile — PAWSON 
457 
The features of the internal anatomy have 
already been described. 
DISTRIBUTION: Cladodactyla crocea is most 
commonly found at the southern tip of South 
America, about the Straits of Magellan, and 
along the eastern coast of southern South Amer- 
ica, as far north as the mouth of the Rio de la 
Plata. The species is also known from Kerguelen, 
South Georgia, and Antarctica (Coulman Is., 
Hut Point, and Franklin Is.) (Bell, 1908). C. 
crocea has been taken between low-tide mark 
and 4,300 m, but is most common to depths of 
about 30 m, often associated with seaweed. 
Genus Stereoderma Ayres, 1851 emend. 
Panning, 1949 
Pentactella Verrill, 1876. 
DIAGNOSIS: Tentacles 10. Calcareous ring 
simple, without forked processes. Body wall de- 
posits are knobbed plates, all of the same shape, 
and arranged in one layer; no tables, no rosettes, 
no cups. (After Panning, 1949.) 
TYPE SPECIES: Stereoderma unisemita (Stimp- 
son). 
REMARKS: The genus Stereoderma contains 
about 12 species at the present time. Four of the 
species have a circumpolar distribution when 
considered together. 
S, leoninoides (Mortensen), Auckland and 
Campbell islands. 
S. godeffroyi (Semper), west coast of South 
America 20°-40° S (Deichmann, 1947). 
S. laevigata (Verrill), southern end of South 
America, Falkland Is., Kerguelen Is., Ma- 
rion Is., the Crozets, Antarctica. 
S. perrieri (Ekman), southern Chile, Falkland 
Is., South Georgia. 
These four species seem to be closely related 
to each other, and their distribution parallels 
the case of certain species of Tr achy thy one 
(Pawson, 1962). 
Stereoderma laevigata (Verrill) 
Pentactella laevigata Verrill, 1876, p. 68; Studer, 
1876; Studer, 1879; Smith, 1879, p. 271. 
Cucumaria laevigata Theel, 1886^, p. 57, pi. Ill, 
fig. 5, pi. IV, fig. 13; Lampert, 1886, p. 
828; Ludwig, 1898*2, p. 32, pi. II, fig. 25; 
Herouard, 1901, p. 44; Perrier, 1905, p. 22; 
Herouard, 1906, p. 12, pi. 2, figs. 5, 6; Bell, 
1908, p. 2; Heifer, 1917, p. 164; Ekman, 
1925, p. 56, text fig. 11; Deichmann, 1947. 
Cucumaria s errata Theel, 1886*2, p. 73. 
Stereoderma laevigata Panning, 1949, p. 422. 
DIAGNOSIS: Tentacles of equal size, feet re- 
stricted to the ambulacra, calcareous ring simple. 
Spicules as oblong plates with one end denticu- 
late, sometimes knobbed with a reticulated net- 
work; they are numerous in smaller specimens, 
more scattered in larger ones. Tube feet have 
end plates and three-armed rods. Tentacles with 
perforated rods; introvert with four-holed but- 
tons sometimes with an external reticulum. 
Total length up to 120 mm. (After Deichmann, 
1947.) 
MATERIAL EXAMINED: Sta. 37, one specimen. 
remarks: The single specimen is small (total 
length 8 mm), and is strongly contracted, with 
many deep transverse wrinkles. Colour in alco- 
hol is light brown. The calcareous deposits are 
typical of this species and need no further dis- 
cussion here. Stereoderma laevigata is a species 
which is readily recognised because of its dis- 
tinctive calcareous deposits. 
DISTRIBUTION: Deichmann (1947) notes that 
S. laevigata is known from the southern tip of 
South America, the Chile coast, Falkland Is., 
Kerguelen Is., the Crozets, Marion Is. Bell 
(1908) reported specimens from the vicinity of 
McMurdo Bay, Antarctica, to depths of about 
41 fathoms. 
Genus Pseudocnus Panning, 1949 
DIAGNOSIS: Tentacles 10. Calcareous ring 
simple, without posterior processes. In the body 
wall are knobbed plates of two types in two 
layers. (After Panning, 1949.) 
TYPE SPECIES: Pseudocnus kollikeri (Semper). 
Pseudocnus dubiosus (Semper) 
For synonymy see Panning (1950). 
DIAGNOSIS: Medium-sized, length up to 100 
mm. Tube feet in five bands, numerous in the 
dorsal ambulacra. Tentacles bushy, of unequal 
size. Calcareous ring simple. Deposits numerous 
oblong knobbed plates (of average length 0.12 
mm) with one end denticulate, and four-holed 
