AMPHIPDOA STEBBING. 629 



exhibited five spines along the outer margin and apex. The 

 telson has a pair of small spines at the obtusely triangular apex. 

 Length, not more than twice the breadth. 



Locality.— Oft' Wata Mooli, from 54 to 59 fathoms. 



Genus D ODE CAS, Slebbing. 



Dodecas, Stebbing, Ann. Mag. Nat. Hist., (5), xi., 1883, p. 207. 

 Dodecas, Stebbing, Chall, Rep., Zool., xxix., 1888, |)p. 547, 1232. 

 Dodecas, P. Mayer, Flora Fauna Neapel, xvii., 1890, pp. 4, 6, 



8, 15, 105, &c. 

 Dodecas, P. Mayer, Siboga Expeditie, xxxiv., 1903, p. 29. 



Dr. Mayer, when adding a second species to the genus in 1903^ 

 remarks that the diagnosis of the genus remains unaltered, and 

 gives its characters as mandibular palp three-jointed, flagellum 

 of second antennse at most five-jointed, first peraeopod with normal 

 number of joints, second wanting, third with four free joints, 

 branchial vesicles on peraeon segments 2-4, pleon in the male with 

 three, in the female with two pairs of a])pendages. 



A slight change is now required, since the species about to be 

 described attains a greater number than five in the joints of the 

 second antennae. It may be distinguished from its companions as 

 follows : — 



, / Body smooth 1 . Dodecas elongata, Stebbing. 



\ Body with spine-like processes — 2. 



{Body of male six-spined; flagellum of 

 first antenna; seven-Jointed 2, Dodecas hexacentrum, Msiyer. 

 Body of male ten-spined ; flagellum of 

 first antennse more than seven-jointed 3. Dodecas decacentrum,STp nov. 



Another mark by which the new species is distinguished from 

 D. hexacentricm is found in the branchial vesicles, which do not 

 decrease in size successively backwards, the middle one being 

 notably the largest. 



DODECAS DECACENTRUM, sp.7iov. 



(Plate Ix.). 



Stations 35, 37, 57. 



This species so much resembles Dodecas hexacenirum, the 

 Australian species described by Dr. Paul Mayer, tuat at the first 

 glance 1 took it for granted that its name was already established. 

 On closer examination this view proved untenable. Fortunatel)- 

 the specimens which Dr. Mayer received from Watson Bay, Port 



N N 



