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FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



bids, in addition to the lack of conspicuous spinu- 

 lation on the anterior and posterior faces of the 

 rami, the endopodal segments are not broadened, 

 nor is the lateral margin lamelliform and produced 

 distad in a prominent spiniform process. Otiier 

 distinguishing characteristics may be forthcoming 

 from consideration of the mouth parts, especially 

 the mandibular dentition, and the number of 

 setae on the first and second maxillae. It should 

 be stressed that thorough revision of the Scoleci- 

 thricidae, suggested previously by Vervoort (1951), 

 and restudy of extant tharybid material is neces- 

 sary to resolve the present confusion. 



Within the Tliarybidae further revision is 

 needed to complete the foundation laid down by 

 Brodski. It appears that PsevAotharyhis Scott 

 must be removed from the family. According to 

 Scott (1909a) the generotype {P. zetlandicus 

 Scott) is distinguished from Tharybis by the lack 

 of sensoriform filaments on the second maxillae 

 and by the truncate nature of the mandibular 

 gnathal lobe. As mentioned, the sensoriform 

 filaments are characteristic of all other known 

 species of Phaennidae, Scolecithricidae, Diaixidae, 

 and Tharybidae. Although their function re- 

 mains to be established, it seems obvious from 

 preliminary examinations (unpublished data) that 

 these filaments are significant, if not vital, sensory 

 receptors. Moreover, many other workers have 

 already suggested their probable sensory function. 

 It does not seem reasonable, therefore, to assume 

 that these filaments are secondarily lost in 

 Pseudotharybis , nor is there any evidence that 

 Scott's genus represents primitive tharybid stock. 



There are also fundamental diflFerence^ betiveen 

 the tharybids and known species of Pseudotharybis 

 regarding the mandibular gnathal lobe. In con- 

 trast to that described by Scott for Pstudoiharybis, 

 the tharybid gnathal lobe is typically elongate and 

 the teeth, excepting the two most ventral, tend 

 to be spiniform or styliform. 



Although Scott's (1909a, b) descriptions of both 

 Pseudotharybis and his two species included there- 

 in, zetlandicus and dubia, are inadequate for deter- 

 mination of their actual phyletic relations, the 

 eventual removal of these taxa from the tharybid 

 complex appears a virtual certainty. For exam- 



ple, there are several interesting points of similarity 

 between Pseudotharybis and Drepanopsis Wolf- 

 enden. Pending restudy of Scott's material how- 

 ever it is proposed that the genus and its species 

 be treated as incertae sedis. 



Genus Parundinella, new genus 



Description. — Tharybids resembling those of 

 the genus Undinella, according to Sars (1900:51) 

 and Brodski (1950:275), although considerably 

 smaller in size. Cephalon fused with thoracic 

 segment I, thoracic segment IV fused with 

 segment V; terminal portions of fusion seg- 

 ment IV-V produced posteriad in lobiform or 

 spiniform processes; genital segment symmetrical, 

 swollen laterad at midportion, ventral portion at 

 most only weakly produced. Abdomen with 4 

 segments in female, 5 in male; anal segment in 

 both sexes reduced in length, considerably shorter 

 than preceding segment. Rostrum with simple 

 bifurcated basal portion; each bifurcation arti- 

 culating with a slender filament. First antennae 

 with segments 8-9, 24-25 fused in female; seg- 

 ments 8-10, 20-21, 24-25 fused in male. Mandi- 

 bular gnathal lobe elongate; only 3-4 monocuspi- 

 date spiniform teeth present, confined to 

 dorsalmost portion of lobe. First maxillae with 

 inner lobe 1 moderate' in size, not broad or truncate. 

 Second maxillae with lobe 5 bearing two sensori- 

 form filaments, one normal seta, one enlarged 

 falcate seta; terminal segments with 5-6 sensori- 

 form filaments; filaments occasionally with apical 

 flagellum. Exopodite of legs 1-4 three-segmented ; 

 endopodite of leg 1 one-segmented, leg 2 two- 

 segmented, legs 3-4 three-segmented. External 

 exopodal spines of legs 2-4 ornamented with small 

 denticles along upper and lower margins. Female 

 fifth legs minute, two-segmented; terminal seg- 

 ment with one or more distal acuminate processes 

 and one robust medial spine bearing ventral 

 spinules. Male fifth legs biramous, asymmetrical; 

 left exopodite three-segmented, left endopodite 

 two-segmented; right exopodite two-segmented, 

 right endopodite in part fused with second basal 

 segment. Remaining structures as in family. 



P. spinodenticula, new species, is herewith des- 

 ignated the generotype of the new genus. 



