5 271 



is fastened by ligament to the epiotir of the skull and reaches backwards about 

 as far as the anterior coalesced part of the vertebræ. Its upper surface is flat, and 

 more or less observable through the skin, laterally to the median nuchal shields; 

 the lower surface carries a thin vertical lamella, originating from its posterior half, 

 to enlarge the face of muscular attachment. Much smaller, but still of consider- 

 able size, is the anterior member of the uppermost ventral row : it is in front con- 

 nected by ligament with another separate ossification, which, passing over the 

 branch given off from the posttemporal to the first vertebra, is fastened to the 

 pterotic of the skull; thus it is from the outside covered by the posttemporal. The 

 "inscription" itself lies below the plate representing the coalesced transverse pro- 

 cesses of the anterior vertebræ and dissolves behind into a bundle of long fibres. 

 Generally the anterior members of the whole system of "inscriptiones tendineæ" 

 are the stoutest. Into the lowermost ventral double row project parts of the endo- 

 skeleton, viz. the posterior ends of the postclavicle and the coracoid; while the 

 former bone ends as a needle, the latter forms a bundle of threads. In a similar 

 way most of the ossified tendons, or "inscriptiones", are split up at both ends — 

 more or less irregularly dichotomously ". 



Endoskeleton. 



The vertebral column consists of 60 vertebræ, 24 (25) abdominal and 36 

 (35) caudal. The four anterior abdominal vertebræ (PI. I, figs. 9, 10, PI. II, fig. 10) 

 are elongated and coalesced into one piece; but distinct sutures show the composi- 

 tion of originally separate elements. This part takes up about one-fifth of the 

 whole length of the vertebral column. Seen from below (PI. I, fig. 9) the corpora 

 do not show much of the usual type; only the posterior one is more like a normal 

 vertebral body, otherwise the combined neural arches and the coalesced transverse 

 processes constitute the dominant part of the whole. The spinous processes form 

 one vertical crest (PI. I, fig. 10), the combined transverse processes a similar one on 

 each side, sloping somewhat downwards and narrowing posteriorly. The single 

 elements are immovably joined through sutures. 



Closer examination of the lower surface will show that the bodies of the 

 second and third vertebra are longer, the first and especially the fourth shorter; 

 (in a specimen, where the whole coalesced part is 61 mm. in length, the first body 

 is 14 mm., the second 17 mm., the third 18, and the fourth 12 mm.). The front 

 end of the first corpus has partly preserved the usual type, but the posterior part, 

 behind the openings for spinal nerves and blood vessels (n), is elongated and modi- 

 fied; the two following have both their ends elongated and modified to about the 

 same extent, as will be evident on looking at the position of the nerve-openings; 

 of the last vertebra only the anterior part is elongated and modified: here the 

 nerve-openings n are found at the posterior end, and the posterior part of the 

 transverse process appears separated as an independent process, as is the case with 

 the following free abdominal vertebræ. The transverse processes on the second 



