102 AUSTRALASIAN ANTARCTIC EXPEDITION. 



P. crocea, it has only been recorded since that date in the " Challenger " 

 report. Grube's material appears to have been but a single specimen, which 

 was obtained between Heard Island and the Crozets. That collected by the 

 " Challenger " came from Kerguelen. 



I regard the present as a different species since Grube describes two 

 pairs of gills in some detail, and he makes no mention of the four membranes 

 springing from the axis; he describes the gill as foliaceous " quasi lanceolata,." 

 Mclntosh gives a brief account of a mutilated anterior end of a worm which 

 he ascribes to Grube's species. His figure (pi. XLVII, fig. 11), agrees in 

 general form quite closely with the worm herein described, but is without 

 any gills. In the text he writes (p. 427), " the next segment bears dorsally 

 the marks of four branchial processes on each side." 



His figure shows three pairs of pit-like structures, which are no doubt 

 the " channels " that I describe above, and which I suppose Grube refers to 

 as " areolse." Mclntosh seems, however, to interpret them as the base^ of 

 gills. They have the same relation to one another and the same position on 

 the segments as I have described. It may be very likely that he had before 

 him the present species. 



As both these accounts are brief, and as only one figure of this 

 interesting genus has been published, it has seemed to me worth while to give 

 rather a detailed description of the worm. 



Genus AMYTHAS, gen. nov.* 



AMYTHAS MEMBRANIFERA, sp. nov. 



(Plate 10, figs. 124-132.) 



A single individual of this remarkable worm was obtained from a depth of 325 

 fathoms in Commonwealth Bay. 



It is imperfect posteriorly, lacking, however, only a few segments, and consists 

 of a head and thirty segments, measuring 60 mm. in length, with an anterior diameter of 

 12 mm., which diameter decreases posteriorly till at the end of the fragment it is only 

 5 mm. The anterior region is a good deal contracted, and the animal was ruptured 

 about half-way along its length, and broke into two pieces on being handled: 



As in other genera, the body is divisible into two regions, thoracic and abdominal ; 

 the former is indicated by the seventeen pairs of notopods with capilliform chsetae, which 

 are absent in the abdomen. The thoracic region appears to be strongly contracted, so 

 that probably the dimensions of the worm just given are not quite correct. The whole 



* The name is formed by transferring the initial " S " of Samytha to the end. 



