COLOMASTIGIDAE : ACANTHONOTOZOMATID AE n S 



lower lip lacks inner lobes. The 2nd joints of peraeopods 1-5 are slender and quite 

 distinct from those of brazieri. 



Distribution. Kerguelen; 'Gauss' winter station. Probably also McMurdo Sound 

 and South Orkney Islands. 



Colomastix castellata, n.sp. (Fig. 64). 



Occurrence: St. 51. Falklands. 1 immat. (J 2-5 mm., 1 ovig. $ 4 mm. from sponge. 



Description. Closely resembling fissilingiia , but distinguished by the shorter telson 

 with its castellated margin, and the stouter peduncles of the uropods, especially that of 

 uropod 3, which is scarcely longer than wide. 



Gnathopod 2 of the ? resembles that of fissilingua as here figured. Gnathopod 2 

 of the c?, which is evidently not fully adult, is stouter, 5th joint triangular, but not so 

 short as in the full-grown pusilla, 6th joint oval, palm oblique, distinguished from hind 

 margin only by its armature of setae, finger short and stout. The inner lobes of the 

 maxilliped are apically separate as in fissilingua . 



Fig. 64. Colomastix castellata, n.sp. a. Gnathopod 2 of (J. 

 b. Telson and uropods 1-3. 



Remarks. There is no need to defend the specific status of this form; its own 

 castellated telson is sufficient. In all the 15 specimens of fissilingua, which I have 

 examined, there is no hint of a multiplication of the marginal slits on the telson. More- 

 over, the telson is different in shape in the two species, and the difference in the peduncle 

 of uropod 3 is quite appreciable. 



Family ACANTHONOTOZOMATIDAE 



Stebbing, 1906, p. 210. 



Barnard, 1930, p. 345 (references). 



This family is far better represented in the southern hemisphere, especially in the 

 Antarctic and sub-Antarctic regions, than in the northern hemisphere. Every suc- 

 cessive Antarctic expedition has brought back additional examples of known forms as 

 well as new forms. 



There is evidently a great variety of forms in the Antarctic regions, but it is as yet 

 impossible to say whether this variety is due to variation within specific limits. In the 

 study of the Discovery collection more difficulties have presented themselves than in 



15-2 



