334 
88, 
89. 
90. 
91. 
92. 
93. 
94. 
95. 
96. 
97. 
103. 
104. 
105. 
106. 
107. 
MR. W. B. S. BENHAM ON THE MUSCULAR 
Mid-ventral entapophysio-pygal. 
Externo-ventral entapophysio-pygal. 
Interno-ventral entapophysio-pygal. 
Externo-dorsal entapophysio-pygal. 
Mid dorsal entapophysio-pygal. 
Tnterno-dorsal entapophysio-pygal. 
Internal sternal slip from 7 (a tergo-pygal). 
External sternal slip from 7 (a tergo-pygal). 
Internal sternal slip from 8 (a tergo pygal). 
External sternal slip from 8 (a tergo-pygal). 
A slip from 73 to the third entapophysis. 
A slip, partly from 2 and partly from 73 to 
fourth entapophysis. 
A slip from 2 to fifth entapophysis. 
A slip from 2 to sixth entapophysis. 
Terminal portion of 2 (the ventral entapophysio- 
plastral), 
112. Muscle from a sclerite (p) on mesosomatic 
appendage to the outer lobe of the same. 
113. A slip from 20 to sclerite (#) on the meso- 
somatic appendage, 
114. A muscle from sclerite (p) on mesosomatic 
appendage to the inner’ lobe of the same. 
115. A slip from 48 to sclerite (p) on the meso- 
somatic appendage. 
1.-v1. Prosomatic appendages. 
yi.-xu1. Mesosomatic appendages. 
vita. Immovable spine belonging to the first meso- 
somatic segment. 
vuta.—xm1a. Movable spines corresponding to the 
last five segments of the mesosoma and the 
first of the metasoma. 
PLATE LXXII. 
The floor of the animal (natural size) after removal of muscles and viscera. It 
shows the raised subfrontal area (sfa), the great arching of the chitinous 
floor at the sides (cen), whilst along the line of attachment of the appendage 
there is a nearly vertical dip; the walls of this hollow being formed by 
the entocoxites and the intervening membrane. In the middle of the 
prosoma or thorax is seen the cut cesophagus (@), in front of this the 
camerostome (cam), and behind it the “ promesosternite”; behind these 
again are seen a pair of cavities leading into the chilaria (metasternite). 
The transverse hollows (vii—x11) in the mesosomatic floor are the entrances 
to the spaces between the plates of the mesosomatic appendages; the 
hollow tendons (ts) of the branchio-thoracic muscles are seen. On the 
post-abdominal sternal region (p.ad.st) are seen the areas of attachment of 
some of the pygal muscles. Behind this is the cut rectum, and then the 
post-anal spine or “ pyge.” On the left the wall of the mesosoma has been 
cut away to show the canal (ca), which runs forwards to the front part of the 
mesosoma, and holds blood-vessels and nerves. 
PLATE LXXIII. 
The carapace and heart have been removed, and the alimentary canal. Fig. 1 isa 
more superficial dissection than fig. 2. 
Fig. 1. On the right side the dissection is more superficial than on the left: the tergo- 
coxals (24, 25) are seen attached to the “ knob” of the entocoxites. That 
of the first appendage (24) is seen nearer the middle line than the rest. 
