CESTRACIONTID^:. 
26 3 
arranged, sharp distally, rounder and more nodose proximally ; the 
denticles are very large, placed upon a longitudinal elevation of the 
posterior face. 
42512. Two much abraded spines of one individual, free from matrix. 
The posterior face exhibits the median longitudinal eleva¬ 
tion ; and the exserted portion of the first measures 0-355 
in length, that of the second 0*255. Purchased. 
P. 3231. Anterior dorsal spine, about 0*425 in total length, exhib¬ 
iting two alternating series of very large posterior den¬ 
ticles ; with three imperfect cephalic spines. 
Enniskillen Coll. 
38544. Anterior spine, 0*48 in total length, the denticles towards 
the extremity smaller and more numerous than usual. 
Purchased , 1864. 
P. 5869. Crushed and broken spine, with larger denticles, exserted 
portion 0*34 in length. Enniskillen Coll. 
39853. Much curved crushed and broken spine, the exserted portion 
measuring about 0*275 in length. Purchased , 1866. 
P. 2165, Imperfect anterior spine. Egerton Coll. 
P. 2166. Crushed spine, about 0*42 in total length. Egerton Coll. 
P. 2802. Spine about 0*35 in total length, with several characteristic 
denticles. Enniskillen Coll. 
P. 4279. Large crushed spine. Enniskillen Coll. 
P. 3164. Large crushed spine, 0*435 in total length, with a few 
characteristic denticles. Enniskillen Coll. 
20006. Posterior dorsal spine, about 0*23 in total length. 
Johnson Coll. 
P. 5866. Imperfect posterior dorsal spine. Egerton Coll. 
P. 5870. Less incomplete posterior dorsal spine, with characteristic 
denticles, the exserted portion measuring about 0*19 in 
length. 
P. 2166 e. Corresponding spine, with very numerous closely arranged 
lateral ribs. Egerton Coll. 
P. 4327. Imperfect much curved posterior spine. Enniskillen Coll. 
