48 INTRODUCTION. 



specimens were dredged up on the coast of the Isle 

 of Man, they were extremely active, and on fir^t 

 inspection had a strong resemblance to small Sand- 

 eels. That so many striking deficiencies, as are im- 

 plied in these statements, should exist in a true fish, 

 could scarcely have been credited ; and the most 

 assiduous efi*orts of skill to supply their places, 

 would overtask the ability of the most ingenious. 

 In fact, it was only an extensive and intimate ac- 

 quaintance with the minutiae of Nature's works 

 as exhibited in the lower links of the animated 

 scale, and more especially of embryonic forms, 

 examined with the aid of powerful microscopes, 

 that could have enabled the indefatigable author 

 of the Paper under review, to have reached those 

 satisfactory conclusions with which he has so re- 

 cently enriched the annals of science. Referring 

 the curious reader, for minute and ample details, 

 to the ]\Iemoir read to the Royal Society of Edin- 

 burgh in May last (Yol. xv. p. 247), we now pro- 

 ceed to state very shortly the mechanism and 

 principles by which the phenomena of life in this 

 singular animal must necessarily be conducted. 



We have already stated that there are no true 

 vertebrae, and, in fact, no bones nor cartilages in 

 the composition of this animal's frame-work. The 

 skeleton consists only of a series of sacs, assuming 

 particular forms according to their several positions, 

 and appearing flattened in the spinal column, and 

 cylindrical in the place of the fin bones. The spinal 

 column consists externally of a fibrous sheath, and 



