246 



PICTURESQUE SKETCHES 



size from most of those of the other secondary deposits. 

 They include, however, a number of families referred 

 to those two orders of fishes which now infinitely ex- 

 ceed the other two in number and variety of form 

 (the ctenoids and cycloids), but which till the chalk 

 had not been introduced upon the earth. Among the 

 chalk fishes there are also some of the sauroid family, 

 among which the species of a genus called Macro- 



Fig. 106 



Fig. 107 



SCALE AND COPROMTE OF MACROPOMA. 



poma were the most abundant and the most pre- 

 daceous. This fish was about eighteen inches or two 

 feet long : the head occupied nearly one-third of the 

 whole length, and was provided with strong jaws arm- 

 ed with numerous sharp conical teeth. The body was 

 covered with oblong scales (106) studded with hollow 

 tubes. The fins were powerful, and strengthened with 

 bony spines, which were probably defensive ; and 

 the whole skeleton is of robust proportions, and in- 

 dicative of great strength. Some specimens of this 

 fish have been so well preserved, that not only do 

 the gills remain, but the whole stomach may be seen, 

 with its membranous walls solidified, and with -a 

 number of coprolites in the abdominal cavity (see 

 fig. 107). 



