LYSIANASSIDAE 4I 



Genus Socarnoides, Stebb. 



Stebbing, 1888, p. 690 and 1906, p. 47. 

 See also Schellenberg, 193 1, pp. 6, 22. 



Although there are no representatives of this genus in the ' Discovery ' collection, I 

 make no apology for introducing the following discussion on these Antarctic or sub- 

 Antarctic forms. (But see also under Acidostomella cnltrifera, supra p. 32). 



The type species is kergueleni, Stebb. 1888. 



In 1888 Stebbing, with one of S. I. Smith's specimens of " Lysianassa" kidderi before 

 him, pointed out the differences between it and Socarnoides kergueleni, and in 1906 

 assigned the former to the genus Nannonyx, Sars 1891. 



In 1909 Chilton united S. kergueleni, Ephippiphora kroyeri, White, N. thomsoni, 

 Stebb., and L. stebbingi, Thorns., with kidderi, Smith, but under the later generic name 

 Nannonyx. 



Stebbing then referred (1910, p. 571) N. thomsoni to a new genus Parazvaldeckia, 

 which agreed with Waldeckia in possessing accessory branchiae. 



In 1922 Tattersall accepted Chilton's synonymy and Stebbing's genus Parazvaldeckia, 

 and expressed the hope that this form, described under at least half a dozen specific 

 names and referred to three genera, had at last come to rest. But if all these "species " 

 are really synonymous, he defeated his own object by adopting the oldest specific name 

 and the latest generic name. Monod (1926) adopted Nannonyx, and Stephensen (1927) 

 followed Tattersall. The name should be Socarnoides kidderi (Smith). 



But it appears to me to be very doubtful whether all these forms are legitimately 

 united. 



In 1921 Chilton (1921 a, p. 35) was able to distinguish two of the forms he had 

 previously united : a form which he refers to Ephippiphora kroyeri (using the preoccupied 

 generic name) and another which he refers to Nannonyx kidderi, with Parazvaldeckia 

 thomsoni as a synonym. I feel sure that our knowledge of these forms is still inadequate, 

 in spite of Chilton's words (1909, p. 617) that "this species has already been fully de- 

 scribed by various other authors ". Some points of conflict in these descriptions may be 

 discussed. 



The accessory branchiae were first mentioned by Stebbing (19 10) and led to the in- 

 stitution of the genus Parazvaldeckia "from its agreement with Waldeckia in possessing 

 accessory lobes to the branchial vesicles". Presumably they are present on segments 

 2-6, but neither Stebbing nor Stephensen (1927, p. 301) state the actual number. It is 

 not fair to assume that Stebbing overlooked them in describing S. kergueleni. Nor are 

 they mentioned by Sars in the description of Nannonyx gdesii. We may therefore 

 separate a form Parazvaldeckia thomsoni (Stebb.), New Zealand, which is further 

 characterized by having the postero-inferior angle of pleon segment 3 "acutely up- 

 turned" (Stebbing, 1906, p. 36). The 3rd uropod is very short with the inner ramus 

 almost rudimentary, as in Nannonyx. But the character of the epistome and upper lip 

 is unknown. 



