setts caudce brevi-pilosis ; lamina caudali ovali-lunceolata, cari- 

 nata, denticulata. 



Long, toti corporis 2 poll. ; lat. clypei I poll. 



Lepidurus viridis, Baird, Proceedings of Zool. Soc. 1850, t. 17- f. 1- 



Hab. "Van Diemen's Land." Museum Britannicum. 



This species resembles considerably the Lepidurus productus. It 

 is two inches long, and has the tail-setae nearly as long as the body. 

 The carapace and whole body are of a fine green colour ; the cara- 

 pace of a rounded oval form and covering about two-thirds of the 

 body. The edges of the notch in the posterior part of the carapace 

 are strongly toothed, and those of the inferior half of the carapace 

 are very finely serrated. The keel running down the centre is well 

 marked and projects a short way beyond the edge of the notch. The 

 tail-setse are beset with very numerous short hairs, and the flap be- 

 tween them is of an oval lanceolate form, and has the keel beset 

 with short sharp spines and the edges finely serrated. The first pair 

 of feet or rami only slightly extend beyond the edge of the carapace. 



Spurious Species. 



Apus caudatus, De Kay, Nat. Hist. New York, Part 6, Crustacea, 

 p. 61. 



In the Journal of the Academy of Sciences of Philadelphia for 

 1818, vol. i., Mr. Say describes a parasitic Crustacean livmg on the 

 Calianassa major (a malacostracous Crustacean), found on the coasts 

 of the Southern States of N. America and of East Florida. He 

 names it the Binoculus caudatus ; and in the Nat. Hist, of New York, 

 Mr. De Kay refers this species to the order Phyllopoda and to the 

 genus Apus, though he says, " I place it here with some hesitation." 

 This animal being parasitic is no doubt referred by Say to the genus 

 Binoculus of Geoffroy, (equivalent to the genus Aryulus, and which 

 must be placed in the order Pcecilopoda,) and not to the genus Bino- 

 culus of Leach, as De Kay supposes, which is the Apus of authors. 



Order Ostracoda. 



Family Cypridid^. 



Genus Cypris. 



1. Cypris Belcheri, Baird (Tab. XXIII. fig. 4). Testa lucente, 

 albida, elongata, striata, supra ai'cuata, infra sinuata ; extre- 

 mitute anteriore latiore, margine compressa, rug at a ; extre- 

 mitate posteriore mucronata. 

 Long. ^ poll. ; lat. 1 lin. 



Hab. ? "From Sir E. Belcher's Collection, along with some 



freshwater shells from the islands of the Eastern seas." Museum 

 Britannicum. 



The carapace valves or shell is of an elongate and narrow form, 

 having the anterior extremity considerably broader than the posterior, 

 and flattened on the margin, which is marked with a good many raised- 

 looking striae, which give it a puckered appearance. The posterior ex- 

 tremity is pointed and acute. The upper margin of the carapace is 



