THE COPEXHAGEX MLTSEFM AND OTHEE SOrECES. 421 



Accoi'diug to present iufovmation, therefore, it seems proper to j^lace in different 

 genera the Lyttelton Harbour specimens here described, and the original Iphigeiiia 

 typica Thomson. It has been earlier jDointed out by von Martens that the name 

 Iphlgenia is much preoccupied. The new name iphinotus, therefore, will take its place, 

 should it appear hereafter that the maxillipeds in Thomson's sijecies were really four- 

 jointed, but accidentally defective. On the other hand, if Thomson's figure show the true 

 state of the case, -when that is made clear, it will be necessary and time enough to give 

 his orenus a new name. 



But the two species, Iphinotus Chiltoni and Ipliigenia typica are in many points so 

 closely alike that, while they perhaps belong to different genera, perhaps also they are 

 but one species. In addition, however, to the recorded difference in the maxillipeds, 

 there is a difference in the perseojjods, the fourth pair having its second joint subequal to 

 that in the third pair in the Lyttelton Harbour specimens, but considerably smaller in 

 those described by Mr. Thomson. Again, the latter are said to have the " telson about 

 as broad as long, nearly semicircular " ; whereas in the Lyttelton Harbour specimens it is 

 much broader than long and slightly angular at the apex. Apparently also in the first 

 described specimen the dorsal line is much more strongly tuberculate. The validity of 

 all these marks of distinction remains to be determined by future observation. 



BiRCENNA Chilton. 



1884. Bircenna Chilton, ' Transactions of the New Zealand Institute,' vol. xvi. p. 264-. 



Body broad. Head not rostrate. Antennae short, subequal, both pairs very slender ; 

 second with prominent gland-cone. Mandibles without palp. First maxillae with inner 

 plate carrying an apical seta, outer plate having eight apical spines ; position of palp 

 marked, but no trace of palp apparent. Maxillipeds with outer plate not extending 

 beyond the inner; palp four-jointed, fourth joint small, not unguiform. Eirst and second 

 gnathopods with the hinder apex of the sixth joint a little 2:)roduced. Pifth perseopods 

 larger than fourth, fourth than third. Pleopods all biramous, and all with the peduncles 

 broadly produced laterally. First and second uropods with unequal curved rami. Third 

 uropods each consisting of an apically bitid plate, not covered by the triangular telson. 



This genus, represented by the single New Zealand species, Bircenna fulvus Chilton, 

 stands apart from the rest of the family by many of its features. Among the less 

 obvioits are the characters of the first maxilloe and maxillipeds, the first maxillae having 

 an inner plate, which seems to be \a anting in the other genera, and eight teeth instead of 

 five on the outer plate, while in the maxillipeds the outer plate does not, as in the other 

 genera, extend beyond the inner plate. I am indebted to my friend Dr. Chilton for the 

 opportunity of dissecting a specimen of Bircenna fulvus. 



58* 



