A New British Pantopod, 299 



Dr. Dohrn admitted the probability that his Clotefiia might be 

 identical with Tanystylzmi, but, in the absence of information 

 as to the number of genital openings, he refused to positively 

 refer his species to the latter genus. Prof. Schimkewitsch, 

 however, in a recent valuable paper' on some genera of 

 pycnogons, states that the male genital openings in the species 

 of Tanystylum correspond with those of Clo tenia. He 

 accordingly does not hesitate to sink the latter genus in the 

 former. In accordance with this view, I refer to our new 

 BritivSh form as Tanystyhwi coiiirostre (Dohrn). 



The genus Tayiystyluni, then, now added to the British 

 fauna, is to be recognised by its circular disciform body without 

 evident segmentation and with fused lateral processes ; its 

 conical proboscis not doubled beneath the body ; the extreme 

 reduction of its chelifori to knob-like vestiges without a trace 

 of jointing ; the presence of palps with joints varying in 

 number from four to seven ; the possession of ten -jointed 

 false legs with simple spines in both sexes, and the opening of 

 the genital ducts of the male on the second coxal joints of the 

 three hinder pairs of walking-legs. The affinities of the genus 

 are with Afumothea, of which several species have long been 

 known from our coasts, and it should be classed in the family 

 Anwiotheidce with many other genera, all characterised by more 

 or less vestigial chelifori, but possessing, in either sex, both 

 palps and false legs. In Dr. Hoek's great work' on the " Chal- 

 lenger" pycnogonida this family is styled Colloseiideidce, but 

 Ammothea, being the earliest described, and, perhaps, the most 

 typical genus of the group, seems entitled to furnish the family 

 name. Prof. Sars, in his beautiful monograph ^ of the North 

 Atlantic pantopods, considers this group of ordinal value and 

 divides it into three families — Anwiotheidce, Pasithoidce, and 

 EurycydidcB. I cannot think, however, that the distinctions 

 between these subdivisions entitle them to family rank. 



All students of the pantopoda have considered the genus 

 Ny77iphon, with its elongate clearly segmented body, fully- 

 developed chelifori, ten-jointed palps, and ten-jointed false legs 



1 W. Scliimkewdtsch. " Notes sur les genres des Pantopodes. Phoxi- 

 chihis and Tanystylum ." Arch, de Zool. Exp el Gen. (2) ix. , 1891, pp. 503-522. 



2 P. P. C. Hoek. " Report on the Pycnogonida." Zoology of the Challenger. 

 London, 1881. 



" G. O. Sars—" Den Norske Nordliaus Expedition. Zoologi. Pycnogo- 

 nidea." Christiana, 1891. 



A 2 



