jaa re 
748 Cincinnatd Soctety. of Natwral History. | 
enough even for’so small a creature to. swim, The legs of the female 
seem, however, scarcely so well adapted for swimming as those of the 
male. I-refer the species “provisionally to Tachidius, as it seems. to 
belong ¢ there more properly than in ‘Canthocamptus, 
- Drapromus (?) KENTUCKYENSIS, n. sp. 
Plate A and B.—Figure 12,- -Diaptomus (?) kentuckyensis. The outer line represents’ the 
male;-the dotted inner line the outline of the female; fig. 13, abdomen of female; ‘fig. 14, 
right ‘antenna, male; fig. 15, left antenna, male; fig. 16, antenna of female; fig. 17, posterior 
- foot, male;-fig. 18, last foot of: male; fig. 19, maxilliped of first pair, female; fi oe ante- 
nules male and female; fig. 21, mandible; fig. .22, 2d eee foot, female; . 2B, first 
‘swimming foot of female. aS 
The species is white and transparent. The abdofien of the male 
has five, that of the female only four segments. Cephalathorax with 
five distinct segments, but when crushed under pressure the head ap- 
pears to divide into four segments. The organs as represented in the 
figures,—length from apex of head to end of terminal sete, L 5 mm. 
Antenne as long as the body. | 
_ For several years in succession, I have taken it frum the same a 
. in‘a small lake or pond, in Linden Grove cemetery, in Covington, 
~ Kentucky, in May; but have not' met with it elsewhere.. The differ- 
ences in thé male and female abdomen, suggest a doubt whether it 
“properly | belongs i in Diaptomus, which strictly has five joints in the 
abdomen in both sexes. The thorax here has only four distinct | 
segments beside the head, though under pressure the head and ° 
. thorax may be separated into nine seoments. In D. castor, according 
to Baird, the antenne have twenty-six joints. In this: species the 
right antenna has only twenty-four in the male, and the left has 
-twenty- six; otherwise it is very similar to'the same organ of D, castor, 
except as to the number, position and character of its ciliz, as to which 
it differs decidedly, since according to Baird, D. castor has each joint 
furnished with one or more sete, and the terminal one with five (see 
fig. 14 as to this species). D. castor, according to Baird, has the short 
‘branch of the antenule, consisting of six joints. In this species, the 
‘articulation of this joint is very indistinct, and there are, I think, os 
joints, some of them being very small and indistinct; there are nine 
plumose sete, each of which appears to me to spring from a. distinct | 
joint. Baird’s first joint seems to me to -be resolvable into three; the 
second branch is longer than the ‘first. This species is evidently quite 
distinct from D. castor, ahd it may be doubtful whether they should be 
placed in the same genus. It is also: evidently quite distinct from D. 
pallidus, Herrick; and from D. longicornis, Herrick; and ‘from all the 
_ other species with which Tam acquainted, especially’ as to ae different 
numbers of joints: in the abdomen’ in the sexes.’ 
we 
