1232 THE VOYAGE OF H.M.S. CHALLENGER. 



Second Perseopods as nearly as possible like the first perseopods, both pairs being 

 without armature, except a few microscopic hairs or cilia. 



Tliird Perseopods missing ; the muscles running to this pair and the place of 

 articulation are rather behind the centre of the segment. 



Fourth and Fifth Perseopods missing, articulated at the extremities of their respective 

 segments. 



Length of female, without the antennae and hind limbs, a fifth of a inch ; length 

 of the second gnathopod of the male, with the finger open, more than a tenth of an 

 inch. 



Locality. — Port Jackson, Australia; depth, 2 to 10 fathoms. Three defective 

 specimens, an adult male, a female with the marsupial plates fully developed, and another 

 female of the same size with the marsupial plates quite small. 



Remarks. — It seems in the highest degree probable that this is the species described 

 by Mr. Haswell as Proto novse-hollandise, but his account of the first and second 

 perseopods does not agree, being as follows : — " First pair of pereiopoda slender, as long as 

 the second and third segments of the pereion, with a slight tooth on the posterior margin 

 of the propodos. Second pair much larger than the first or third, rather longer than the 

 cephalon and the first two segments of the pereion, the carpus, propodos, and dactylos 

 short, the propodos armed with four spines and a row of serrations on its anterior border." 

 These observations may be true of the male, and yet not apply to the female, but it 

 seems unlikely that the second perseopods should differ so much from the first, since in 

 the other known species of the genus these two pairs, so far as they have been described, 

 are in close agreement. 



Genus Dodecas, Stebbing, 1883. 



1883. Dodecas, Stebbing, Ann. and Mag. Nat. Hist., ser. 5, vol. xi. p. 207. 



Mandibles with an elongate three-jointed palp. 



Loiver Antennae with a flagellum of more than two joints. 



The First and Second Gfnathopods and Fourth and Fifth Perseopods fully developed ; 

 the First and Tliird Perseopods feebly developed, the Third not having the full number 

 of joints ; the Second Perseopods wanting. 



Branchial Vesicles on the second, third, and fourth segments of the perseon. 



Pleon undivided. 



Uropods two-jointed. 



The generic name is derived from the Greek SwSe/cas, a set of twelve, this genus 

 being distinguished from the rest of the Caprellidse by having twelve limbs (in six pairs) 

 attached to the perseon. 



