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rests on the upper margin of the anterior part of liie succeeding vertebral arch. 

 On the very long vertebræ 2 — 5 the arch is quite low, especially in A. strigata, 

 where the spinous processes of this region lie almost horizontally, pressed against 

 the arches; in this species the spinous processes are likewise longer than in sciitata 

 (in strigata the process on the 1st vertebra reaches posteriorly almost to the anterior 

 margin of the 3rd vertebra, that on the 2nd vertebra to the 4th vertebra and so 

 on). On the 6th vertebra only the anterior part is elongated; the two parts of the 

 arch are therefore close to one another (especially in strigata). F'rom the 7th 

 vertebra the common vertebral form in fishes appears; on the 7th the anterior 

 and posterior parts of the arch are separated by a narrow, but high groove; on 

 the 8th the groove between the two parts of the arch is quite short, on the 9th it 

 reaches right in to the centrum; posteriorly the anterior part of the arch gradually 

 assumes the form of a large "articulating process"; on the 18th vertebra it can 

 hardly be seen. 



The transverse process, as mentioned, is lacking on the 1st vertebra; they are 

 present however on the 2nd— 6th and developed in the form of long lamellar 

 projections for connection with the lateral plates of the dorsal cuirass (cf. text- 

 fig. 1). The transverse process on the 2nd is prolonged forwards beyond the hind 

 end of the 1st vertebra; posteriorly it is connected by a kind of suture with the 

 anterior end of the next transverse process. Opposite the centre of the body of 

 the vertebra there is a somewhat thicker, middle part (or axis), which corresponds 

 in position to the interspace between 2 scuta; behind this axis there is a deep 

 incision for the spinal nerve (fig. 1, n). The front part of the transverse process 

 fits into the double lamella on the inner side of the 1st lateral plate, the hind 

 part into the lamella on the next plate; the connections between the lateral plates 

 and the transverse processes on the 3rd and 4th vertebræ are arranged in a similar 

 manner, the processes having the same structure as on the 2nd; further, the part 

 of the 5th vertebra's transverse process lying in front of the outlet for the nerves 

 is also inserted into the lamella on the 4th lateral plate, but the posterior part of 

 this transverse process as also the transverse process on the 6th vertebra is only 

 joined by connective tissue to the 5th lateral plate, which has no lamella in scutata 

 but a low one in strigata. As can be seen from fig. 1, the 6th vertebra is of a 

 different pattern from the preceding 2 — 5; only the part lying in front of the hour- 

 glass shaped constriction of the vertebra is prolonged and only the corresponding 

 part of the transverse process in front of the nerve outlet is lamellar-like; the part 

 behind this is more in the shape of a process. The bodies of these 6 long vertebræ 

 are quite distinctly of the typical hour-glass shape, most modified in the 1st and 

 6th, where in the former case the anterior part of the hour-glass is quite short, in 

 the latter the posterior part. 



The vertebræ 7 — 13 (see PI. II, fig. 1) bear lateral outgrowths in a similar 

 position to the lamellar processes above described; but they only spring from the 

 anterior half of the vertebra; they are triangular in shape, directed obliquely 



