tec 
1883.) 1 81 (Packard. 
tion of the genus; in all the other genera, as in all Diplopod myriopods, so 
far as we are aware, the sixth pair of legs are like the others. 
In each genus of Lysiopetalide, except Lysiopetalum itself, the eighth 
pair of legs, ¢. ¢.,, the pair situated on the sixth segment or that bear- 
ing the male genital armature, is much modified. In Lysiopetalum lac- 
tariwm the seventh and eighth pair of feet, ¢ ¢., those before and behind 
the male genital armature, are as well developed as the other legs ; it is 
probable that, owing to the large and long genital armature, reaching 
beyond the basal joints of the legs, that the latter needs no change in form 
to assist in clasping the female. Tn Pseudotremia, however, the eighth 
pair of legs are much modified, though still six-jointed ; the two basal 
joints are much swollen, of very irregular shape, the coxe being consoli- 
dated ; the rest of the leg is much smaller, slender, four-jointed, the third 
joint of the leg or basal joint of the free portion being as long as the three 
terminal joints less the long claw. In the three lower genera, Trichopet- 
alum, Scoterpes and Zygonopus, the eighth pair of legs are on the same 
type; the two latter genera being evidently derived from the out-of-door 
form, Trichopetalum. In these three genera the eighth pair of legs are 
much aborted, two-jointed ; the onter joint about thrice as long as the 
basal, and either unarmed or ending in a claw. 
The Male Genital Armature.* This apparatus has only been incidentally 
studied. In Lysiopetalum lactarium and Pseudotremia the lamina externa 
and lamina interna are much as in other Chilognaths. In the first-named 
genus the armature is about as large asin the Julidw; in the Pseudotremia 
itis minute. In Pseudotremia and in Scoterpes and Zygonopus there is 
developed either upon (Pseudotremia) or at the base of the outer lamina 
a minute spinous appéndage which we have not noticed in the figures of 
Vosges, Wood or Humbert, .In each genus observed by us the armature 
presents characteristic features, so that they appear to have generic but no 
family characters. In Scoterpes, Trichopetalum and Zygonopus the arma- 
ture is minute and rudimentary. In. Scoterpes its outer lamina is tridentate 
at the enlarged end, while the inner lamina is sac-like and simple. 
LystoprraLtum Brandt. 
Julus Say, Journ. Acad. Nat. Sc., Phil., ii, part i, 104, 1821. 
Lystopetalum Brandt, Recueil, 42, 1840. 
Spirostrephon Brandt, Bull. Sci. Acad., 1841. St. Pet., 1840. Recuil, p. 
90, 1840. 
Platops Newport, Ann. & Mag. Nat. Hist. xiii, 266, 1844. 
Lysiopetalum Gervais (in part), Aptéres, iv, 188, 184’7, 
* The genital armature of Julidse have been described and figured by EK. Voges 
in Zeitschrift far wissenschaftliche Zoologie, xxxi, 150, 1878. He regards the 
seventh segment as the *‘Copulationsring” of the male, and says, “at the bot- 
tom of the deep sac-like membranous connection of the sixth and seventh body- 
rings lies the Copulations-Organ”’ of the female, 
\ 
