,G. M. Thomson. — Notes on New Zealand Crustacea. 205 



Institute during the session of 1878.* As generic descriptions of Crustacea 

 are not accessible to most of the readers of our "Transactions," I have 

 thought it advisable to supply these in all cases where the genera are new 

 to this country. The various species are mentioned in the following order, 

 viz., Schizopoda, Isopoda, Amphipoda, and Phyllopoda. 



ScHIZOPODA. 



Fam. MYSID^. 



Thorax covered by a carapace, which extends to the base of the ocular 

 peduncles, and is produced into a rudimentary rostrum. Mouth situated 

 near the base of the antennae. Six pairs of thoracic feet, provided with a 

 well-developed palp. Tail of five plates, forming a swimmeret, as in 

 Macruura decajwda. 



G-enus Mysis, Latreille. 



External antennae beneath the eyes, bearing two terminal filaments. 

 Internal antennae beneath the external ; first joint furnished with an elon- 

 gated laminar appendage ; two succeeding joints slender and cylindrical, 

 terminated by a long, filiform, multi-articulate flagellum. Pedipalps two 

 pairs, entirely pediform ; first pair three-branched ; second pair two- 

 branched. Six pairs of thoracic feet, consisting each of two branches, 

 decreasing in length from before backwards, and formed for swimming ; 

 last two pairs furnished with a flabelliform appendage. In the female 

 these acquire a great development, and constitute two large semi-circular 

 plates, folded below so as to form an oviferous pouch, in which the young 

 pass through their first stage of development. Abdomen very slender, 

 tapering, elongated, nearly cylindrical. 



1. M. denticulaia, G. M. Thomson, (Ann. & Mag. N.H., ser. V., Vol. VI., p. 1.) 



Fig. 1. 



Female. — Carapace rather slender and short, with a short, triangular, 

 acute rostrum. Peduncle of the internal (upper) antennse extending to the 

 extremity of the scale of the external antennas ; second joint very short ; 

 third the widest. Scale of external antenna somewhat broad, with a tooth 

 at the outer angle, and long cilia on its inner side, and at its extremity. 

 Middle lamella of the tail entire, toothed on each side, and with two strong 

 teeth at the apex. Lateral laminae exceeding the central one ; the inner 

 narrow-lanceolate, acute, and furnished with long hairs on each side ; the 

 outer obtuse, with the apical half narrowing, ciliated only at the extremity 

 and on the inside, and with a few stout teeth about the middle of its outer 

 margin. Length '5 inch. 



Hab. — Dredged in Dunedin harbour, 4-5 fathoms. 



* See " Trans. N. Z. Inst." Vol. XI., p. 230, et seq. 



