100 THE VOYAGE OF H.M.S. CHALLENGER. 



Arcturus myops, F. E. Beddard (PI. XXII. figs. 5-8 ; PI. XXV. fig. 8). 



Arcturus myops, F. E. Beddard, Proc. Zool. Soc. Lond., 1886, pt. i. p. 106. 

 The present species differs from any other Arcturus at present known by the fact 

 that the eyes are entirely or almost entirely aborted. The two specimens which I 

 include under the above specific name were dredged from a depth of 700 fathoms, off 

 New Zealand. The only trace of eyes left are a pair of rounded elevations on either 

 side of the head, which, as far as could be made out from the examination of a specimen 

 mounted entire in Canada balsam, are not facetted and contain no pigment ; the 

 structure of the integument on these ocular convexities displayed no recognisable 

 differences from the integument elsewhere. 



O 



The largest of the two individuals measures 10 mm. in length, and appears to be 

 a male ; the smaller specimen is of the same sex. 



The margin of the head is excavated by a semicircular notch dorsally and anteriorly ; 

 the lateral margins are straight. 



The first four thoracic segments are subequal in length ; each is ridged posteriorly, 

 the ridge as usual widening out laterally to occupy the whole of the segment ; in the 

 fourth thoracic segment the ridge is higher dorsally than in the three anterior segments. 

 This ridge in all the segments is closely beset with fine granulations. Anteriorly, between 

 the posterior ridge and the anterior margiu of the segment, is a short ridge likewise 

 covered with numerous granulations ; the first thoracic segment has two of these ridges. 



Of the three posterior thoracic segments the first is the longest ; on each is a ridge- 

 like elevation closely beset with granulations. The abdominal segments and the caudal 

 shield are similarly roughened by numerous tubercles, the caudal shield is somewhat oval 

 in form, tapering to its posterior extremity, which is slightly bent upwards. 



The proximal joints of the antennae (PI. XXV. fig. 8) and of all the thoracic limbs 

 (PI. XXII. figs. 7, 8) are furnished with numerous tubercles. The uropoda are covered 

 with minute granulations, and close to the inner margin of each of these appendages 

 is a row of sharp-pointed, backwardly-directed tubercles. 



Station 169, July 10, 1874, off New Zealand; lat. 37° 34' S., long. 179° 22' E.; 

 depth, 700 fathoms ; bottom temperature, 40° F.; blue mud. 



Arcturus studeri, F. E. Beddard (PL XXIII. figs. 1-4). 



Arcturus studeri, F. E. Beddard, Proc. Zool. Soc. Lond., 188G, pt. i. p. 111. 



A number of specimens of a small Arcturus, from the shores of Kerguelen, form 

 the type of a new species which I dedicate to Professor Studer, who has done so much 

 to increase our knowledge of the fauna of Kerguelen. 



It is characterised as follows : — 



Extreme length 28 mm., length of antennae 30 mm. 



