8 
AUSTRALASIAN ANTARCTIC EXPEDITION. 
The appearance of the skin agrees with that figured by Selenka for the variety 
(pi. IV, figs. 38, 39). and with that of the species (fig. 37). 
The tentacles are in three or four rows of about ten in each row. As I had to 
cut open the introvert in order to study them it was impossible to ascertain whether 
they would have the appearance presented by the figure given by Theel for this form 
(pi. V, fig. 67), but altogether I estimate that there are thirty tentacles. 
Internally, too, the worm agrees with Theel’s figure (pi. V, fig. 68), though the 
number of intestinal coils varies with the length of the animal. Thus, in the largest 
specimen I counted twenty-eight coils wrapping round a similar number of internal 
upwardly-directed coils, the whole forming a close spiral measuring 20 mm. across. 
In a smaller specimen (from Station 1), which is 48 mm., including the introvert, the 
number of coils is twenty-four, while in the individual D, which is only 28 mm. in 
length, the number of coils is sixteen. The two dorsal retractor muscles are attached 
to the body wall at a point 8 mm. behind the anus; the ventrals arise 40 mm. behind 
that aperture. 
There are no contractile tubules on the oesophageal vessel. 
Localities —- 
Station 1, 350-400 fathoms (22 xii 13) (one). 
Station 2, 318 fathoms (28 xii 13) (four). 
Distribution .—This variety has been obtained from Magellan Strait, Tierra del 
Fuego, Falkland Islands, Picton Island, Cape Adare, Graham Region. 
Remarks— Five closely-allied species have been obtained from the Antarctic and 
Subantarctic seas—namely, P. margaritaceum, var. capsiforme Baird, from 
the Falkland Islands; I J . fuscum Mickaelsen, and P. antarcticum Mich., and 
P. georgianum Mich., from South Georgia; P. socium Lanchester, from Cape 
Adare. 
P. georgianum appears to be distinguished from Michaelsen’s other 
species by-its short introvert, and its smooth translucent body wall with large 
dark papillae on the skin. 
* The two other species from South Georgia are so closely related that 
even Michaelsen himself (1889) thought it not unlikely that they are in 
reality varieties or sub-species of P. margaritaceum (as also probably is 
P. capsiforme Baird). 
Although a study of Michaelsen’s account of these two species makes 
it difficult to separate them, Herubel was able to do so, for he records specimens 
of each from Port Charcot, though the differences on which he relies are very 
slight. 
