266 MB. A. D. MICHAEL ON A NEW [Mar. 14, 



rostrum. The hinder part of the cephalothorax widens greatly, 

 its edge being the double curve known as the line of beauty. 

 This edge is formed by a large raised roll ; the median portion 

 of the cephalothorax is also raised, but between the two, in 

 the hinder part of the cephalothorax, is a large, shallow depres- 

 sion or dimple. There are a pair of hairs close together near the 

 anterior edge of the rostral tube. On each side there is a very 

 long hair near the edge of the body a little in front of the first 

 leg, a similar hair near the posterior corner of the cephalotliorax, 

 and a shorter one about midway between them, also one pair on 

 the dorsum of the cephalothorax ; these, and all other hairs on the 

 creature are simple and setiform. 



Ahdomen. — The anterior edge (progaster) has a somewhat 

 exceptional form ; the central portion (about half the width) 

 projects boldly into the cephalothorax, is concave anteriorly, and 

 runs out laterally so as to form a short horn or point. Erom the 

 central projection the line on each side of the body runs back at 

 an angle, but this portion also is concave anteriorly ; it forms a 

 raised roll with a large shallow depression or dimple behind it 

 like that on the cephalothorax. When the creature is very full}' 

 fed all these depressions vanish, they also disappear after death. 

 There are two pairs of hairs on the central projection of the 

 progaster, the inner pair are the longer. There are also two other 

 pairs of hairs on the notogaster (the hinder the longer), and two 

 hairs on each lateral edge (the hinder the longer). The anus 

 forms a short, median, posterior projecting point when seen from 

 above, but a long slit when seen from the ventral surface ; it is 

 formed of two thin blades on edge lying close against each other, 

 but capable of being separated widely posteriorly. 



Underside (figs. 2 and 3). — The sternum is a triangular plate 

 sending out band-like projections on each side parallel to the edge 

 of the rostral collar, and a similar but straight piece posteriorly in 

 the median line ; this is longer in the male than the female. The 

 epimera of the first pair of legs are formed by the lateral pro- 

 jections of the sternum and a branch arising from the sternum and 

 passing behind the legs. Those of the second pair of legs are 

 somewhat Y-shaped sclerites, which in the male are joined at their 

 posterior ends to the posterior end of the sternum by short cross 

 pieces. In the female they are \\ider apart and not attached. 

 The epimera of the third and fourth legs are short right-angled 

 pieces in the male. The vulva is between the two posterior pairs 

 of legs ; but advances more forward than the insertion of the legs ; 

 it is protected anteriorly by a large semi-annular sternite, and has 

 well-marked chitinous labia. The male organ (fig. 9) lies rather 

 further back ; it is protected by a slightly elliptical (almost circular) 

 plate, slightly truncated behind. This plate covers the lougish 

 curved penis (fig. 10) and the some\A'hat elaborate skeleton A^hich 

 supports it (fig. 9). This consists of a horseshoe-shaped sclerite 

 with thick projecting posterior ends joined by a broad band, from 

 a central projection of Avhich the penis arises ; the anterior end of 



