MUSEUM OF COMPARATIVE ZOOLOGY. 73 



like Acanthephyra debilis A. Milne-Edwards (Ann. Sci. Nat., 6"" series, XI. 

 No. 4, p. 13, 1881), and it is possible that the species may be identical, — or, on 

 the other hand, that they may belong to very different genera. Milne-Edwards 

 says : " Le genre Acanihe^jhyra semble rattecher les Penceus, les Regulus, les 

 Oplophorus et les Ephyra," but gives no characters which enable me to tell how 

 the genus differs from Miersia (^Ephyra), though the species of Miersia appear 

 to be very little known, as I have already remarked, and Milne-Edwards may 

 have had opportunities of examining typical specimens, to which, however, he 

 does not allude. Miersia Agassizii is evidently very distinct from any of the 

 species of Acanthephyra described by Milne-Edwards. 



MENINGODORA,* gen. nov. 



Integument throughout very thin and membranaceous. Body compressed 

 laterally and the carapax dorsally carinate anteriorly, with a short triangular 

 rostrum, a well-developed branchiostegial spine as in Miersia, and with an 

 antennal and hepatic sulcus, above which there is a carina which is continued 

 back along the dorsal limit of the branchial region, — a form of areolation 

 strongly recalling the Penseidse. Antennal scales broad and foliaceous, but all 

 the other articular appendages essentially as in Miersia. The branchiae (phyl- 

 lobranchise) have the same structure and arrangement as in Miersia, except 

 that there is apparently but one arthrobranchia at the base of the external 

 maxilliped,. making in all eleven branchia; and six epipods each side. 



Although differing very conspicuously in general appearance from the species 

 of Miersia here described, this genus is very closely allied to them, as a com- 

 parison of the figures of the appendages will show, but it is sufficiently dis- 

 tinguished by the characters above given. Its relation to Hymenodora f is more 

 obscure, though perhaps equally close. In Hymenodora the body is not com- 

 pressed, and according to Buchholz's figure the epimera of the second somite of 

 the abdomen do not overlap the epimera of the first segment, but are of the 

 same form as the succeeding epimera, and this seems to be confirmed by the 

 clause in Sars's generic diagnosis, " epimeris seqvaliter rotundatis." More- 

 over, the endopod of the first maxilliped, according to Sars, is not segmented 

 ("parte terminali (propria) angusta, inarticulata "). On the other hand, the 

 number of the branchiae is apparently the same, though Sars's statement 

 (" branchiae utriuqve 6, antica et postica simplex, ceterae bipartitae ; praeterea 

 adsunt branchiae supplementariae, indivisae, laminaceae, basi maxillipedum l""* 

 et 2* paris affixae ") does not make this perfectly clear. 



* M^i'i7^, a membrane ; dopd, skin. 



t Hymenodora glacialis G. 0. Sars, Archiv Mathem. Naturvid., Kristiania, II. 

 p. 341, 1877 {Pnsiijliae glacialis Bucliliolz, Zweite deutsche Nordpolfahrt, II. p. 279, 

 PI. I. fig. 2, 1874). 



