Tachidius crassicornis, n. sp. ope lame). - (PL VIII. fig 
Length, exclusive of tail sete, -7 mm. Body moderately stou 
cephalo-thoracic segment longer than the next two together, the f 
' produced into a short rostrum, Anterior antenne shorter ‘than the ee 
body segment ; that of the female six-jointed, stout, and densely setiferous 
towards the extremity, a small sensory filament springs from fifth joint.. 
The proportional length of the joints are nearly as in Abe formula 
201029 5S 320 ee 
12 eae iG 
The anterior antennz in the male form powerful grasping organs, s, closely 
resembling those of Tachidius brevicornis (fig. 17). Posterior antenne 
short, three ointed, the last joint nearly aslong asthe preceding two together ; 
a small one Jointed secondary branch springs from the end of the first 
joint. Mouth organs nearly as in Tachidius brevicornis. The first four — 
pairs of swimming feet nearly alike, both branches three-jointed, the first. 
joint of the inner branches of all the four pairs smaller than either the 
second or third joints. The fifth pair in the female moderately large 
atid foliaceous, furnished with three equal and plumose terminal seta ; a 
plumose seta springs from a rounded basal part on the anterior ‘margin ‘of 
the female fifth pair, which may represent a rudimentary second branch, 
The fifth pair in the male are very small, subquadrate, and furnished with 
one small and two moderately long sets near the inner angle and one at 
the outer angle; the first abdominal segment in the male is armed with 
prominent lateral appendages, which are easily observed without dissection, 
and which consist of a broad, but short, basal part bearing three unequal 
Spiniform and plumose marginal setae, the inner one being longer than ~ 
either of the other two. Caudal stylets short, about as long as the last. 
abdominal segment, and furnished with four sete#,—the inner and outer — 
ong plain and very small, the other two plumose and elongate ; the inner 
of the two principal sete is much longer than the other; and the basal 
part of the proximal half is broader than the remaining portion ; the broad. 
part, which is of nearly equal breadth throughout, merges abruptly into, 
the more slender portion as shown in the figure. Ovisac single, large, 
with a number of large ova. ; 
Hubitat.—Near Culross on the upper estuary of the Forth ; not very, 
rare. Obtained February 1892. 
This species comes near Pachidius brevicornis (Miiller), but differs in 
the form of the anterior antenne, which are rather stouter and shorter 
and sixjointed ; in the first joint ‘of the inner branches of-the first four 
pairs of swimming feet being smaller than the other two joints ; and in 
the form of the fifth feet in the female. - rae 
aera longicaudata,* n. sp. (provisional name), : CP). abs figs. 1-18), 
Body slender ; length, exclusive of tail sete, 1 mm. (25th of an inch), 
_ Anterior margin of first body segment squarely truncate; forehead produced 
= into a short blunt rostrum. Anterior antenne longer than the first 
-cephalo-thoracic segment, elongate, and sparingly setiferous ; that of the 
female eight-jointed, of the male nine-jointed; the male antenne are 
distinctly hinged between the sixth and seventh joints, and indistinctly 
_ between the third and fourth joints. A longsensory filament springs from | 
the end of the fourth joint in both sexes ; the porportional length of the 
joints of the female and male antenne are nearly as in the annexed 
formulae | 
