Chilton. — Some New Zealand Amphipoda. 3 



Though I have all along been convinced that Stebbing was right in 



combining Panoploea debilis G. M. Thomson with Pherusa novae-zealandiae 



G. M. Thomson, it has been a little difficult to understand the differences 



, in the descriptions of these species, and how it was that Mr. Thomson came 



to describe the same form as two different species in two successive years. 



In January, 1914, in the collections of the Dunedin Museum, I found 

 a bottle labelled " Pherusa novae-zealandiae G. M. Thomson, Dunedin ; 

 Type," in the handwriting of the late Captain Hutton, who was Curator 

 of the Museum at the time when the species was first described, and 

 through the kindness of Professor Benham I have been able to make an 

 " examination of its contents. The bottle contained altogether ten speci- 

 mens, all more or less imperfect ; seven of them are without doubt the 

 species common in New Zealand and long known under the name PanojjJoea 

 debilis G. M. Thomson. All of these specimens ha.ve lost their antennae 

 except the peduncles, but the character of the gnathopoda, of the pro- 

 jection of some of the segments into dorsal teeth, and of the uropoda 

 and telson, leaves no doubt as to the identity of the species. Of the 

 other three specimens, two, one of them imperfect, are small examples 

 of Parad.exam.ine pacifica (G. M. Thomson), which have apparently been 

 included by accident, and are of no importance in the present discussion. 

 The remaining specimen, which is the largest of the lot, and of which the 

 head and anterior part of the peraeon are missing, is a specimen of a 

 different species altogether, Panoploea spinosa G. M. Thomson, which is 

 no longer considered congeneric with Panoploea dehilis and is placed by 

 Stebbing in a different family. 



It seems evident that these specimens had been grouped together 

 owing to the fact that in all of them some of the segments are produced 

 posteriorly into dorsal teeth and that a portion of the original description 

 of Pherusa novae-zealandiae had been ]3ased on the specimen of Panoploea 

 spinosa: e.g., the statement that "two posterior segments of the pereion 

 and two aifterior segments of the pleon produced dorsally into two teeth," 

 and " three last pairs of pereiopoda much longer than the preceding ; their 

 coxae with comb-like teeth on their posterior margins"; also, '"third seg- 

 ment of pleon with the sides produced posteriorly, and ending abruptly in a 

 serrated margin." The characters thus quoted agree well with this specimen 

 of Panoploea spinosa, and some of them are indicated in the figure given 

 by Thomson in describing Pherusa novae-zealandiae. These points do not 

 show clearly in the very small figures accompanying Mr. Thomson's 

 published paper, for " instead of lithographing the plates, the draughtsman 

 traced them on to a large sheet, from whence they were photo-lithographed " 

 (see Stebbing, 1888, p. 500), and in the process they were so much reduced 

 that many of the points shown clearly in th« original drawings cannot be 

 made out. Mr. Thomson has, however, given me the tracings of the 

 originals, and in the tracing of the figure of the whole animal of Pherusa 

 novae-zealandiae it is evident that the dorsal teeth, the basal joints of 

 the posterior peraeopoda, and the hind-margin of the third pleon segment 

 have been drawn from the specimen of Panoploea spinosa, and not from 

 the genuine Pherusa novae-zealandiae. " The other characters have been 

 based on the specimens really belonging to Pherusa novae-zealandiae, and 

 the description is therefore composite, being based on more than one 

 specimen, as is shown by the statement that the posterior margin of the 

 third segment of the pleon " is almost smooth in young specimens," the 

 " young specimens " being the genuine Pherusa novae-zealandiae, and quite 

 different from the Panoploea spinosa which was confused with them. 



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