330 
MR. W. B. 8. BENHAM ON THE MUSCULAR 
The other muscles attached to the plastron which have been mentioned in previous 
sections are :— 
No. 1, from its posterior process ; 
No. 2, from the dorsal face of the body ; 
No. 3, from the dorsal face of the body ; 
and those from the under-surface, 30 to 47, which go to the prosomatic appendages. 
First: 
Second: 
Third: 
Fourth: 
V. Muscles connected with the six Mesosomatic Entochondrites. 
Muscle No. 5 from the prosomatic entochondrite is inserted here. 
No. 12 (first pair of vertical mesosomatic muscles) is inserted here and passes 
vertically to the carapace. 
No. 5 passes on from its connexion with the first mesosomatic entochondrite. 
No. 12 (second pair of vertical mesosomatic muscles). 
No. 13, the first pair of oblique entapophysio-sternal muscles, passes from this 
entochondrite to the fourth entapophysis. 
No. 62. The first pair of mesosomatic intersternal muscles passing from this to 
the fourth entochondrite. 
No. 63. A similar muscle passing from this to the fifth entochondrite. 
No. 69. A slip from the ventral longitudinal muscle (no. 3) is also inserted here. 
No. 5 continues from the second entochondrite. Also a third pair of vertical 
mesosomatic muscles, no. 12, and a slip (70) from no, 3 are inserted here. 
No. 14, the second pair of oblique entapophysio-sternal muscles, goes hence to 
the fifth entapophysis. 
No. 64, the second pair of mesosomatic intersternal muscles, arises here and 
passes to the fifth entochondrite. 
No. 5 is continued. 
No. 12 is present as the fourth pair of vertical mesosomatic muscles. 
No. 71 is a slip attached here from the great ventral longitudinal muscle, 
similar to the slips 69 and 70. 
No. 15, the third pair of oblique entapophysio-sternal muscles, is inserted here, 
arising from the sixth pair of entapophyses. 
No. 16, a fourth pair of oblique entapophysio-sternal muscles, arising from the 
seventh pair of entapophyses, is also inserted into the fourth mesosomatic 
entochondrite, as shown in fig. 3, Pl. LXXV. In fig. 1, Pl. LXXIV., it is 
represented as inserted into the fifth entochondrite. The drawings have 
been somewhat complicated and difficult to letter accurately. Apparently 
the muscle no. 16 is omitted in fig. 1, Pl. LX XIV., and that to which the 
reference 16 is attached should properly be lettered 17. 
No. 62 arising from the second mesosomatic entochondrite, and noted above, 
is inserted here. 
