410 



THETIS SCIENTIFIC RESULTS. 



spines on the former are much larger, and on the fifth joints 



they are absent. 



The second joint of the fifth pair of legs 

 is equal in length to the three following 

 combined ; it has a well-marked spine at 

 its inferior base ; third joint equal to the 

 sixth ; fourth and fifth as long or slightly 

 longer than broad ; seventh stout, curved, 

 and about one-tenth shorter than the sixth. 

 The last two pairs of legs are smaller than 

 the pair preceding ; the second joints of each 

 are provided with an inferior proximal spine. 

 The pleopods are devoid of any special 

 features. The uropods are lanceolate in 

 shape, and each bears a series of about 

 eight i^mall denticles arranged in an oblique 

 row. 



Three specimens were obtained off Botany 

 Bay, in 50 to 52 fathoms. 



Fifth leg. •' ' 



Fig. 115c. 



ARCTURUS ALCICORNIS, sp. nov. 



(Figs. 116«-c.) 



Station 37. 



Adult female : — Body about 10 mm. long. The frontal margin 

 of the cephalon is slightly excavated ; the externo-lateral borders 

 are produced, and bear three or four spines. There are two 

 prominent spines on the frontal region ; each has an accessory 

 spine immediately below ; the hinder border bears a pair of 

 spines ; these are submedian, and directed outwards ; posterior 

 to the eyes there are two obliquely placed spines on each side, 

 and three similar spines occur on the postero-lateral margins. 



The first segment of the peraeon is a little longer but not so 

 wide as the cephalon ; the second and third are subequal in 

 length, and much wider than the first ; the fourth is about a 

 third longer than any of those preceding, and tapers rapidly to 

 its rather narrow extremity ; the fifth, sixth and seventh segments 

 are very short mesially ; the anterior and posterior borders are 

 excavated and adapted to each other. 



The armature of the peraeon is as follows : — The first segment 

 bears a pair of submedian spinules ; laterally there is a stoutish 

 bifurcated spine on each side, and several spinules on lower 

 margins. The second and third segments are each provided with 

 four stout antlei'-like spines, two of which are lateral and two 

 marginal ; a few small spines occur at the posterior bases of the 

 large branched spines, and several between the latter and the 



