86 ANNUAL EEPORT. 



GENERA CHARACTEKS OF ENTOMOSTRACA. 



The Crustaceans of this order are quite various in form, habits and internal 

 structure. They possess specialized jaws, but there are never more than three 

 pairs of qualities, while m the higher orders there are often six. 



The somnites of the abdomen (that portion of the body posterior to the genital 

 aperture) are devoid of appendages. Though the study of these animals is very 

 fascinating and instructive the task is a difficult one, both on account of the 

 minute size of most of them and the great difficulty of ascertaining with 

 what organs of the higher forms some of the novel instruments seen are 

 homologous. The curious misapprehensions and inaccuracies into which authors 

 have fallen still further complicates the matter. 



The descriptions of these organs, and their functions, must be taken up under 

 the divisions of the order and treated separately. The process of reproduction 

 is particularly interesting in this group, for we have numerous instances of 

 agamogenesis and the Pectostraca are hermaphrodites peculiarly modified Al- 

 ternate generation will be spoken of more particularly under the Daphnioidea. 

 The species described have all been collected and compared with descriptions of 

 previous authors, the new species, it is hoped, will be found sufficiently well 

 defined in connection with the figures given to permit of a ready identification. 



The following table of the families of the order will be useful for reference, 

 while the characters upon which they are founded, and synonyms, will be found 

 in their appropriate places. 



TABULAR VIEW OF ENTOMOSTRACA. 



ORDER ENTOMOSTRACA, 



LEGION I. LOPHYROPODA. 



TRIBE I. CYCLOPOiDBA (here used as equal to Copepoda with the Poecilopoda 

 among he Cormostomata (or EpizoaS) 

 Family 1. Calanidse. 

 Family 2. Cyclopidse. 

 Family 3. Corycaidse. 

 Epizoa? 



. TRIBE II. DAPHNioiD^. (Cladocera.) 



Family 1. Penilidse. 



Family 2. Daphnidse. 



Family 3. Bosminidse. 



Family 4. Polyphemidse. 



TRIBE III. CYPRID^. 



Family 1. Cypridse. 



Sub-family a. Cyprinae. (Cypridse Bd.) 



Sub-family b. Cythrinse. (Cythridae Bd.) 

 Family 2. Halocypridee. 



Sub-family a. Cypridininse. (Cypridinadse Bd.) 



Sub-family b. Halocyprinae. 



