244 "TERRA NOVA" EXPEDITION. 



Astacilla falclandica aucl A. magellanica were described by Ohliu in 1901, and in 

 both species the head is stated to be fused with the first segment of the thorax, and the 

 segments of the pleou all fused together. In the present collection there is a single 

 female specimen, from New Zealand waters, which I am unable to distinguish from 

 A. falclandica, Ohlin, and an examination of its characters has led me to decide that 

 the fusion of the true second thoracic somite with the cephalothorax, the fact that its 

 lateral parts are not expanded to cover the oral area, and the unsegmented nature of 

 the abdomen are characters of generic importance. I have, therefore, instituted the 

 genus Neastacllla for its reception, and would refer A. magellanica to the same genus. 



The genus Neastacllla agrees with Astacilla in having the flagellum of the second 

 antenna composed of three joints, in having the seventh joint of the third to the fifth 

 thoracic limbs represented only by a short nail, in having the last three thoracic limbs 

 robust and bi-unguiculate, and in having four pairs of marsupial lamellae. 



49. Neastacilla falclandica (Ohlin). PL X, figs. 1-3 



Astacilla falclandica, Ohlin, 1901, p. 266, pi. XX, fig. 1 ; Stebbing, 1914, p. 353. 



Occurrence. — Station 96, 7 miles E. of North Cape, New Zealand, 70 fathoms, 

 bottom fauna, one ovigerous female, 8 * 5 mm. 



RemarJcs. — I can find no valid characters to separate this specimen from 

 A. falclandica, Ohlin. The only diS'erence I can find is that, whereas Ohlin describes 

 his specimen as without tubercles or spines, I can detect a few obscure tubercles on the 

 elongate somite of the thorax in mine, which I have attempted to indicate in the 

 figure. The whole body in my specimen is very transparent, and it is with great 

 difficulty that the tubercles can be seen at all. They are very low and not at all 

 prominent. Otherwise the specimen agrees absolutely with Ohlin's description, even 

 to the presence of black pigment-spots all over the body. I have figured the fifth and 

 eighth thoracic limbs to show their general form and structure. Stebbing has already 

 called attention to the minute dactylus on the third, fourth and fifth pairs. The latter 

 author is of the opinion that ^4. magellanica, Ohlin, is synonymous with this species. 

 According to Ohlin, A. magellanica difi'ers from A. falclandica in its smaller eyes, 

 shorter and stouter second antennae, and the absence of black pigment-spots. These 

 diff"erences may be sexual, but Ohlin's specimens of both species were very small, and 

 he does not give the sex. N. falclandica difi'ers from Astacilla niq,rionensis , Beddard, 

 and A. kerguelensis, Vanhoff"en, in having the abdomen unsegmented and without a 

 prominent spine half-way down its lateral margin. 



The species provides further evidence of the wide distribution of some of the 

 Crustacea found in New Zealand waters. 



Genus PSEUDARCTURELLA, nov. 



Diagnosis. — Body of the usual Arcturid form, with a marked bend between the 

 fifth and sixth thoracic somites ; second to eighth thoracic somites clearly marked off' 



