1024 THE VOYAGE OF H.M.S. CHALLENGER. 



A specimen of this species was labelled as having been taken "June 3, 1874, off 

 Port Jackson, 30 to 35 fathoms." 



Station 168, off New Zealand, July 8, 1874 ; lat. 40° 28' S., long. 177° 43'E.; depth, 

 1100 fathoms; bottom, blue mud ; bottom temperature, 37° - 2. One specimen. 



Mr. Haswell, in establishing the species, records it from " Port Jackson (very common 

 at low water among Algae, etc.), Botany Bay ; Port Stephens." 



Remarks. — By the kindness of Mr. G. M. Thomson I have been enabled to dissect a 

 specimen from Lyttelton, New Zealand, of his Moera petriei. In that specimen the inner 

 plate of the first maxillae has only two apical setae, the first pair of side-plates are less 

 outdrawn at the lower front angle, the sculpture of the palm of the second gnathopods 

 differs greatly from that in the Challenger species above described, the hand is without 

 the oreat brush of long hairs or setae, the finger ends obtusely like that of Melita 

 proximo, (obtusata), Sp. Bate, the rami of the third uropods are less broad, each lamina 

 of the telson has four apical spines, and in the fourth and fifth peraeopods the hind 

 margin of the first joint is less convex. On the other hand the description and figures 

 given by Mr. Thomson of Moera petriei, from Port Pegasus, agree so closely with the 

 Challenger specimen above described that I feel bound to withdraw the specific name 

 persetosus engraved on the Plate, and also to accept the conclusion at which Mr. Chilton 

 has arrived, that Megamoera subcarinata, Haswell. and Moera petriei, Thomson, are one 

 and the same species, although presenting some variety of form even in the same sex. 

 Mr. Chilton in the New Zealand Journal'of Science says, " I have both male and female 

 specimens from Sydney, the females resembling those from Lytteltou Harbour, and 

 described in the Transactions of the New Zealand Institute, vol. xv. p. 82. Curiously 

 enough the males agree with those described by Mr. Thomson from Stewart Island, and 

 differ from my Lyttelton specimens in having ' the whole lower surface [of the propodos 

 of the posterior gnathopoda] very densely fringed with two rows of long simple hairs.' 

 These hairs, which are of the same size throughout their whole length, and thus differ from 

 the ordinary setae found in this genus, are entirely absent in the Lyttelton specimens. 

 An interesting question thus arises, but for the present must remain unanswered: — What 

 is the function of these hairs, and why should specimens from Sydney and Stewart Island 

 have them, while those from Lyttelton have not % " Mr. Chilton tells me that he 

 subsequently found that " the form of the propodos is slightly different in the specimens 

 from the two localities. In the Annals and Magazine, when considering the question 

 whether the species presents an example of " dimorphic " males, Mr. Chilton says, " I 

 would like to point out that I have not as yet had a sufficient number of specimens 

 of Moera subcarinata to make me feel quite sure that the two forms are not simply 

 animals of different ages." He refers also to the possibility of alternating forms, as dis- 

 covered by Faxon in Cambarus. As to the long setae of the second gnathopods, my 



