250 Part III.— Tenth Annual Report 



TacMdius crassicomis^ n. sp. (provisional name). (PI. VIII. figs. 14-27); 



Length, exclusive of tail setae, '7 mm. Body moderately stout, first 

 cepkalo-thoracic segment longer than the next two together, the forehead 

 produced into a short rostrum. Anterior antennae shorter than the first 

 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 the formula 



20 • 10 - 3 • 5 ' 3 • 9 

 1 • 2 • 3 ■ 4 - 5 • 6 ' 



The anterior antennae in the male form powerful grasping organs, closely 

 resembling those of TacMdius brevicomis (fig. 17). Posterior antennae 

 short, three-jointed, the last joint nearly as long as the preceding two together ; 

 a small one-jointed secondary branch springs from the end of the first 

 joint. Mouth organs nearly as in TacMdius brevicomis. 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 

 and 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 setae 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 setae, — the inner and outer 

 being plain and very small, the other two plumose and elongate ; the inner 

 of the two principal setae 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. 



Habitat. — Near Culross on the upper estuary of the Forth ; not very 

 rare. Obtained February 1892. 



This species comes near TacMdius brevicomis (Miiller), but differs in 

 the form of the anterior antennae, which are rather stouter and shorter 

 and six-jointed; 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. 



Ameira longicaudata* n. sp. (provisional name)* (PL IX. figs. 1-18). 



Body slender ; length, exclusive of tail setae, 1 mm. (25th of an inch). 

 Anterior margin of first body segment squarely truncate; forehead produced 

 into a short blunt rostrum. Anterior antennae longer than the first 

 cephalo-thoracic segment, elongate, and sparingly setiferous ; that of the 

 female eight-jointed, of the male nine-jointed ; the male antennae are 

 distinctly hinged between the sixth and seventh joints, and indistinctly 

 between the third and fourth joints. A long sensory filament springs from 

 the end of the fourth joint in both sexes ; the porportional length of the 

 joints of the female and male antennae are nearly as in the annexed 

 formulae 



* Referring to the long caudal stylets. 



