REPORT ON ZOOLOGY. 109 



on the Branchipus of Latreille, or, as the author here calls it, 

 Chirocephalus* . 



If to the above works we add a few separate memoirs devoted 

 to particular genera by different individuals, — that of the younger 

 Jurine on Argulus foliaceus published in 1806f, Straus's two 

 memoirs on the genus Daphnia published in 1819 and 1820 J, 

 a third the year following by the same author on the genus Cy- 

 pris§, and Brongniart's memoir on the Limnadia Hermanni 

 published in 1820||, — we shall have enumerated by far the most 

 valuable contributions which have been yet made to our know- 

 ledge of this portion of the Crustacea*^. Straus's memoirs in 

 particular, which for patient research and close anatomical in- 

 vestigation, considering the minuteness of these animals, can 

 scarcely be equalled, deserve the highest commendation . It was 

 principally in consequence of the labours of this observer and 

 those of Jurine, which were subsequent to the appearance of 

 the first edition of the R^gne Animal, that Latreille was led to 

 make such striking alterations in the arrangement of the Ento- 

 mostraca in his Families JVaturelles. These alterations have 

 been already pointed out ; and they clearly show what we may 

 yet expect from further researches into the structure of other 

 groups which have not hitherto received so close an examination. 

 The only recent contributions of any moment, at present known 

 to me, are, a memoir by Dr. Gruithuisen on the Anatomy of 

 Daphnia Sima published in 1828**, a second by Milne Edwards 

 on the structure of the mouth in the Siphonostomous Entomo- 

 straca published in 1833ff, and a third published within these 

 few months by Mr. Thompson on the Artemis salinusXt- The 

 principal object of M. Edwards's essay is to show that notwith- 

 standing the apparent differences between the mouth of the 

 Siphonostoma and that of the rest of the Crustacea, the parts 

 are strictly analogous in the two cases, and there is still kept up 

 a unity of composition. Thompson's memoir contains observa- 

 tions on the gradual development of the j^oung of the Artemis 

 salinus, and the metamorphoses which it undergoes before arriv- 

 ing at an adult state. These metamorphoses are found to cor- 



* This memoir had been previously published in the Journal de Physique for 

 1803, torn. Ivii. t Ann. du Mus., torn. vii. p. 431. 



+ Mim. du Mus., torn. v. p. 380, and torn. vi. p. 149. 



§ Id., torn. vii. p. 33. || Id., torn. vi. p. 83. 



If A treatise on the Monoculi was published at Halle, in 1805, by Ramd'hor, 

 who, according to Latreille, has anticipated Straus and Jurine in somfe of their 

 anatomical researches. I have not seen the work myself. 



•• Nov. Jet. i^-c. Nat. Cur., torn. xiv. p. 368. 



tt -^nfi. des Scien, Nat., torn, xxviii. p. 87. 



XX Zool. Researches, No. 5, Mem. 6. 



