i8 CRUSTACEA OF ALABAMA. 



The fifth foot is two-jointed, the basal joint is short and bears a tubercle carrying a 

 seta .06 mm. long, the terminal segment is terete and bears a spine .10 mm. long api- 

 cally and another as long upon the middle of its inner side. The cement gland is of pe- 

 culiar shape, resembling that of C. parous exactly. The last segment of the abdomen is 

 spiny upon the posterior margin above. The color is usually pale, but may be orna- 

 mented with bluish suffusions. 



Though closely allied with the species in America identified with Sars' C. oithonoides 

 there can be no doubt that two forms occur, this one being nearly exactly like the spe- 

 cies described by Hoeck as C. leeuwenhoskii. The description and drawings are given 

 as a basis upon which to distinguish other allied species. The form from the southern 

 states originally called C. tenuissimus is probably this species though possibly distinct. 

 The use of the name C. simplex for the species may be objectionable. 



FAMILY HARPACTICID.E. 



An enormous family, consisting of much more compactly framed animals than either 

 of the preceding families. The body flattened or sub-cylindrical. Abdomen usually not 

 much smaller than the thorax, from which it is not separated by a sudden constriction ; 

 antennae rather short, 4- to 10-iointed; mandibles strongly toothed, palpate ; maxillse 

 well developed, palpate ; first pair of maxillipedes with strong teeth at the end, second 

 pair usually forming a prehensile claw. The first pair of feet are often turned forward 

 or prehensile ; fifth pair one- or two-jointed, serving as egg supports in the female ; ova 

 sacs single. 



Most species live among sub-aquatic vegetation. 



Nearly thirty-five genera are known and about eighty-five species, only two of the 

 genera being found in fresh-water. 



Genus Harpacticus, Milne-Edwards. 



Body elongated and moderately depressed ; head beaked ; first and second abdom- 

 inal segments in the female united, the abdomen, therefore, in the female, (apparently) 

 4-jointed, in the male 6-jointed ; antennas 9-jointed, in the male greatly deformed by en- 

 largment of the fifth and sixth segments ; antennules with small 2-jointed palp ; palp of 

 mandible biramose and of considerable size ; maxillae with four-spined apical portion and 

 a four-parted spinous palpus ; first maxilliped small and strongly armed ; second maxil- 

 liped very large, chelate ; first foot with both branches two-jointed, the outer being elong- 

 ate ; the following pairs with both rami three-jointed, the second joint of the inner ramus 

 of the second pair in the male is furnished with a long spine and the third has the outer 

 ramus chelate ; fifth feet small, unlike in the sexes. Three species with varieties are 

 now recognized all from the North Atlantic and adjacent waters. Our own species dif- 

 fer but little from the Mediterranean variety of the H. chelifer. The remaining species 

 are H.fulvus, Fischer, and (?) H.flexzis, Brady and Robinson. 



