Cylin(lrop«iyllii9 brevicornis, (fee. 139 



is mucli dilated and deeply notched. The second antenna is 

 three-jointed, the tliird joint hearing six strong spines and a 

 single long s[)ine-like seta (PI. Vll. fig. 1). The external 

 ramns is reduced to a small knob bearing a single seta. 

 The mouth-parts are as in D.fairliensis, consisting of man- 

 dibles, two pairs of maxillae, and a pair of maxillipedes. 

 The mandil)le bears a one-jointed palp with two setae (PI. VII. 

 fig. 2). The maxillipedes are well developed and appear to 

 agree with those of D. fairliensis, as figured by Prof. Sars. 



The swimming-legs are almost the same in both sexes, 

 and are less slender than in D. fairliensis. In the first pair 

 (PI. \\1. fig. 3) the second basal joint bears a strong spine 

 on its inner angle, which is. absent from the succeeding legs. 

 In the male (PI. VII. fig. 4) this spinels curved and slightly 

 barbed. The internal rami of all legs are two-jointed, 

 nearly as long as the external branch, but they differ some- 

 what in the different legs in respect of the setae borne by 

 them. The internal rami of the third and fourth pairs of 

 legs of the male differ from those of the female in having 

 the inner spine of the second joint considerably lotiger, and 

 in having a long spine springing from the middle of the 

 first joint of the fourth leg in space of a short apical spine. 



The fifth pair of legs are the same in both sexes, con- 

 sisting of small knobs bearing each a small lateral seta and 

 three terminal setae of which the middle one is very small 

 (PL VII. fig. 12). 



Length. Female 115 and T3 mm. ; male 1'2 and 1*45 mm. 



The specimens described above form part of the Norman 

 Collection in the British jNIuseum (Natural History), and 

 are labelled " Cylindropsi/l/its Iw.vis, E. Loch Tarbert, Loch 

 Fyne, 1886, T. Scott." (B.M. nos. 452i8-252). I have to 

 express my thanks to Dr. W. T. Caiman and the authorities 

 of the Museum for allowing me to examine them. 



The species differs from D. fairliensis in the form of the 

 furcal rami of the female, in the structure of the antennse, 

 and in certain details of tiie length and arrangement of the 

 seta} of the swimming-legs. 



EXPLANATION OF THE PLATES. 

 Plate V. 



Horsiella breviconiix (Van Douwe), 



Fig. 1. Female, ventral view. 

 Fit). 2. Male, dorsal view. 

 Fig. '6. Male, lateral view. 



