OBSERVATIONS ON THE ASTACIDJE— FAXON. 679 



scaie j the areola, or, in other words, the posterior section of tlie carapace, 

 is much longer, being nearly one-half as long as a line drawn from the 

 cervical groove to the anterior end of the rostrum; the hand, too, is 

 provided witli shorter lingers and the lower half of the hand is more 

 heavily tuberculate both on the inner and outer faces. The number of 

 lateral rostral spines varies from three to five on each side; the number 

 of inferior spines on the rostrum is one or two. In large specimens 

 from Eoto-Iti and I^ airier the sides of the carapace are thickly set with 

 blunt tubercles which become spiny only on the hepatic and pterygo- 

 stomian regions, and along the cervical suture; but in similarly large 

 examples from T^elson (South Island) all tlie tubercles, even those on 

 the branchial regions, tend to assume the form of sharp spines. Finally, 

 in individuals collected at Wellington and in Pelorus River, Marlbor- 

 ough (localities on opposite sides of Cook Strait), a tendency is mani- 

 fested to variation in the direction of Paranephrops zealandkms, inasmuch 

 as the lateral rostral spines are increased in number and reduced to 

 short, blunt teeth, and the antennal scale is short and broad, broadest 

 at the middle, with very convex internal border. The largest of these 

 specimens is only 73 mm. long. The number of lateral rostral spines 

 varies between three and eight on each side, the average number being 

 five. The lower side of the rostrum is in many cases destitute of teeth. 

 In three out of the four specimens from Pelorus Eiver the median carina 

 of the carapace is very prominent, and extends forward from the gastric 

 area half way to the tip of the rostrum. Usually in P. planifrons it 

 runs forward only as far as the anterior postorbital spines. 



The most southern locality where P. planifro7iH has been found is 

 Greymouth, on the western side of the South Island. 



It thus appears, as was first pointed out by Mr. Chilton, that P. 

 planifrons is a variable species distributed throughout the whole length 

 of the North Island (where it is the only species found) and tiirough 

 the northern part of the South Island as far south as Greymouth. 

 Hence it would seem, in the words of Mr. Chilton, "that Cook Strait 

 has not proved so great, or rather so old a barrier to these crayfish as 

 the mountains in Nelson forming the northern continuation of the 

 Southern Alps. As this point seemed to be of some importance in 

 connection with the geogra])hical distribution of the fauna of New 

 Zealand, and as I was ignorant of the configuration of that part of the 

 South Island, I applied to Professor Hutton for information. With 

 his characteristic kindness and promptness, he at once told me that 

 there was no great division (by mountains, that is,) between Nelson 

 and Greymouth, but that the first great division would be along the 

 Kaikoura Mountains and across westerly to Mount Franklin, and then 

 down the Spencer Mountains and the Southern Alps; though the part 

 between the Kaikoura Mountains and Mount Franklin is much broken 

 by rivers, some running north and some south. He also told me 

 that several North Island plants extend to Nelson and down the 



