538 
PROFESSOR E. RAY LANKESTER. 
Segments. 
Tergites. 
| 
10 [3rd pair of lateral spines. 
3rd pair of dorsal pits 
and entapophyses. 
11 |4th pair of lateral spines. 
4th pair of dorsal pits 
and entapophyses. 
12 |5th pair of lateral spines. 
5th pair of dorsal pits 
and entapophyses. 
13 |6th pair of lateral spines. 
6th pair of dorsal pits 
and entapophyses. 
14 |Only in the embryo this 
segment is separate, 
and has a 7th pair of 
lateral spines. 
segment is indicated. 
These three segments 
iy are never expressed 
aud are represented 
by the preanal re- 
— gion of the telson. 
18 
Post-anal spine. 
15 |Only in the embryo this 
Abdominal carapace. 
LIMULUS. 
Sternites. 
Epistigmatic pair of 
sclerites and stigma- 
tic pits. 
Hpistigmatic pair of 
sclerites and stigma- 
tic pits. 
Appendages. 
3rd gill-book pair 
projecting. 
4th gill-book pair 
projecting. 
Kpistigmatic pair of|5th gill-book pair 
sclerites and stigma- 
tic pits. 
projecting. 
None. 
Large and solid scle- 
rite forming the ster- 
num of the *‘Telson,”’ 
i.e. of the pree-anal 
region of potential 
segmentation, which 
includes a soft inva- 
ginate area on which 
opens the ANUS. 
None. 
None. 
None. 
None. 
None. 
