CYCLOPOIDEA. 



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Dr. W. Baird, the author of the learned work on British Entomos- 

 traca has also added to the family a genus, called Alteutha, which is 

 a depressed form of Harpacticus. His work also recognises the genus 

 Cantliocamptm of Westwood, which was instituted, as he shows, in 

 1846, for a group with Cyclops rninutus of Miiller for its type. Milne 

 Edwards, in the third volume of his Histoire Naturelle des Crustaces, 

 published in 1840, referred the species Cyclops rninutus, Miiller, to his 

 new genus Cyclopsina, which was instituted also for the C. castor, one 

 of the Calanidas. Moreover, this author introduced the genus Earpac- 

 twus for the Cyclops chelifer, a related species. The same year Philippi 

 proposed the name Nauplius (Archiv f. Naturg., vi. 189) for a genus 

 identical with Harpacticus ; and in 1844, M. Koch, in his Deutschl. 

 Crust., gave the name Doris to a group having the Cyclops rninutus 

 for its type. Baird, in his recent work, adopts the genus Cantho- 

 camptus of Westwood, with the type C. rninutus, and also, Harpac- 

 ticus, with the type C. chelifer, distinguishing the two mainly by the 

 size of the first pair of legs, this pair being very small in the former, 

 and moderately large in the second. In form, these legs are essen- 

 tially the same, although Dr. Baird's description seems to imply a dif- 

 ference besides that of size; and the distinction he adduces seems not 

 to be important. The groups may, however, be distinct, if, taking the 

 same types, we disregard the size of these legs, and look for a better 

 characteristic to the next pair of legs. In the C. rninutus and several 

 species allied, the branches of this pair of legs are three-jointed, while 

 in the C. chelifer they are two-jointed. On this ground, the genera 

 may both be retained. The body is commonly nearly linear, or nar- 

 rows gradually backward in Canthocamptus, with little or no inter- 

 ruption at the abdomen ; while it narrows abruptly, as far as we have 

 observed, in Harpacticus. The Harpacticus nobilis of Baird has one 

 branch reduced to a single joint, and the thorax is very much thicker 

 than the abdomen. This may be the type of another genus, for 

 which we suggest the name Westwoodia. 



These explanations prepare the way for the following synopsis of 

 the subfamilies and genera of Cyclopidse. 



Subfam. 1. CYCLOPIN^E.— Sacculi ovigeri duo. 



Gr. 1. Cyclops. — Cephalothorax 4-articulatus. Pedes lmi articulo penultimo ad 

 apicem internum elongato instar digiti inimobilis, et digito inobili parvulo setigero. 

 Corpus subcylindricum. Appendix abdominis basalis parva. Antennae anticse 

 feminsG non appendiculatse ; maris articulatione geniculante confectse. 



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