PROFESSOR E. RAY LANKESTER, 
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12 (a).—Ventral aspect of Thelyphonus (from the object). 1 to vi. 
Cephalothoracie appendages ; the first, which is concealed by the coxa 
of the second, is represented as removed from its attachment. sfc. 
Sterno-coxal process of the coxa of the left second appendage. sf}. 
Thoracic prosternite. s¢?. Thoracic metasternite. vi to xvil1. Seg- 
ments of the abdomen. J, 7. Apertures of the right lung sacs in the 
ninth and tenth segments. msg. Muscular stigmata on the sternites 
of the tenth, eleventh, twelfth, thirteenth, and fourteenth segments. 
an, Anus. 
13 (B).—Dorsal aspect of the abdominal segments of the same. _—p. 
Muscular pits corresponding to the entapophyses of Limulus. paf. 
The jointed postanal filament. 
14 (c).—Abdominal segments of the same, with the terga and viscera 
dissected away (after Blanchard). . Nerve cord. zg. Abdominal 
nerve ganglion. J, 2. Pulmonary sacs in the ninth and tenth seg- 
ments. m,_m,m,m. Muscles attached to muscular stigmata of the 
four following segments. az. Anus. pa/. Postanal filament. 
sixth pair of cephalothoracic limbs, we find a pair of closely 
opposed upstanding sclerites, the chilaria of Owen (mets¢ 
1A 
XXVIII, fig. 4, and woodcut, fig. 4). The late develop- 
ment of these pieces, as determined by Packard, as well as 
their position, leaves no doubt that they are not to be re- 
garded, as is supposed by some, as rudimentary appendages. 
They are a paired development of the metathoracic sternal 
area and may be designated metasternites. 
