114 DISCOVERY REPORTS 



Genus Pelagobia 

 Four tentacles. Two pairs of tentacular cirri, a dorsal and a ventral, borne by a single 

 segment which also carries bristles. The dorsal cirrus of the 2nd chaetiger is reduced or 

 absent. The feet are uniramous and carry slender, cylindrical dorsal and ventral cirri. 

 The feet have a single aciculum and compound bristles with denticulated blades. The 

 proboscis is smooth. 



Pelagobia longicirrata, Greeff. 



Fauvel, 1923, p. 192, fig. 72 a-e. 

 Augener, 1929, p. 291, with synonymy. 



Occurrence. St. 17 (6); 41 a (3); 41 b (6); 41 d (5); 41 e (4); WS 40 (4); WS 44, 1000-75001. 

 (i), and 750-500 m. (5); WS 555 (3). 



Specific characters. A small species measuring up to about 12 mm. in length with 

 25 chaetigers. The head is conical and truncated in front. There is a single pair of eyes. 

 Four small thread-like tentacles. The two pairs of tentacular cirri are long and subulate 

 and the first segment has a small pedal lobe with a few bristles. There is no dorsal cirrus 

 on the 2nd chaetiger. 



The following segments carry slender tapering dorsal and ventral cirri. The pedal 

 lobe is conical and has an aciculum and numerous long, delicate compound bristles. 

 These have the end-pieces denticulated, and often the head of the shaft also. The end- 

 pieces have a delicate border on the side opposite the teeth. 



Remarks. I have examined the bristles of a random sample of these specimens and 

 in none can I find any denticulation of the head of the chaetal shafts. In this they differ 

 from the northern representatives of the species. 



P. longicirrata is a very common species in the southern cold-water plankton. 

 Augener found it in the Weddell Sea. 



Genus Mystides, Theel 

 Small, elongate animals. The head is rounded. There is a pair of eyes and four 

 tentacles. No median tentacle and no occipital papilla. Three pairs of tentacular cirri. 



The formula is i + 5 - . The feet are uniramous. Dorsal and ventral cirri foliaceous 

 or more or less globular. Bristles compound. Proboscis with soft papillae. 



Mystides notialis, Ehlers. 



Ehlers, 1913, p. 457, pi. xxix, figs. 1-4. 

 Occurrence. St. WS 226 (i). 



Specific characters. The present specimen measures 13 mm. by 0-5 mm. for 52 

 chaetigers. It corresponds exactly to Ehlers' account. There is a pair of dark eyes and 

 four very slender, transparent tentacles. The first segment is achaetous and carries a 

 pair of tentacular cirri ; the second segment has bristles and two pairs of tentacular cirri, 

 a dorsal and a ventral. All the tentacular cirri are swollen towards the base and are 

 apically slender and filiform. The normal dorsal and ventral cirri are more or less 

 globular. The bristles are compound and have a bifid articulation. The head of the shaft 



