BY W. A. HASWELL. 333 



third ami fourth, and these only for a short distance at their outer ends. In 

 length the legs increase from before backwards, the fourth being much the 

 longest and about half the length of the body in a large specimen. Each con- 

 sists, as in other mites, of six podomeres (PI. xxsvi., fig. 6) in addition to the 

 epimeron. Swimming hairs are not developed on them, there being only a small 

 number of short hairs. At its extremity (PI. xxxvi., fig. 7) each is provided 

 with a pair of strongly-hooked trifid or tridentate claws without sucking disk, 

 but with a stoutish spine. 



5. Coxal or integumentary glarnds. 



The two oval bodies referred to above as the coxal glands may not correspond 

 to the organs so named in other Arachnids, and the name is mainly applied to 

 them here on account of the position of the openings of their ducts on the coxae 

 of the last pair of legs. The "glands" in question (PI. xxxvi., fig. 1, ex) are 

 situated close to the ventral surface behind the central nervous system. Each is 

 divided into about half-a-dozen lobes which converge outwards and forwards to- 

 wards the point from which the duct is given off, and narrow prolongations of 

 some extend into the latter and may reach the aperture. 'The clear substance of 

 which these lobes are composed is very hard in the preserved specimens and in 

 many cases refused to be cut into ' sections, the gland breaking into irregular 

 pieces and tearing up adjoining structures. In one series of sections, however, 

 of an immature female without eggs, it is clear enough that each lobe is divided 

 transverselj' by thin partitions into several (usually four) parts, and that in 

 each of these is a small round body like an indistinct nucleus. On the other hand 

 in some series of sections of full-gi'own specimens with numerous eggs the 

 organ has not broken and the sections of it appear like sections of an almost 

 homogeneous body, staining strongly and uniformly with eosin or erythrosin, 

 and without histological structure. In the smallest specimens which I have ob- 

 tained — minute free-swimming stage — the organs in question are very distinctly 

 divided into lobes and have wide ducts, but the specimens, mounted whole un- 

 stained, are not in a condition to show minute structure. The conclusion to b» 

 derived from the. imperfect data appears to be that, while probably functional 

 in the young animal, these glands become inert in the fixed parasite and their 

 histological structure degenerates. 



Openings of "integumentary glands" are present on the fourth epimera in 

 Teutonia, Limnesia and Limnesiopsis (Piersig u. Lohmann, 1901). It seems pro- 

 bable that the glands in question are of the same nature as the bodies above 

 described; but the latter appear to be very different from the dorsal integu- 

 mentary glands described by Michael (1895) and others in Tliyas and various 

 other Hydrachnids. 



6. Digestive System. 



A slit between the bases of the pedipalpi expands behind into the rounded 

 aperture of tlie mouth which is surrounded by a ring-like thickening of the 

 cuticle. The latter is produced inwards to form the investment of the buccal 

 cavity. The latter gives off the pharynx almost immediately within the mouth- 

 opening (PI. xxxvi., fig. 8), and is continued below the basal joints of the two 

 chelicerae into a dorso-ventrally compressed space which expands laterally and 

 receives at its outer angles the main salivary ducts. 'This space, which may be 

 termed the salivary receptacle {s.r.), is separated from the buccal cavity proper 

 by a fold of the thin membrane forming the floor of both, a fold which lies on 

 a cushion-like elevation and may act as a valve. 



