418 LANCELET. 



would remain motionless, lying flat on its side with its mouth 

 open, and to all appearance dead, for thirty or forty minutes, 

 or longer if not disturbed. Two days after its capture he put 

 a quantity of shell-sand in the vessel, which alarmed it, and 

 for a few seconds it swam with increased velocity, and then 

 suddenly disappeared in the bed of sand at the bottom of the 

 glass. In fifty minutes from this time a third part of its body 

 appeared above the sand in an upright position, and quite still, 

 with the mouth open, and the filaments slightly bent at their 

 extremities; but on agitating the water with a piece of straw 

 the body was partly drawn in; and on repeating the annoyance 

 it disappeared altogether. Mr. Cocks adds that he carefully 

 watched this little creature, with the assistance of a poclcet-lens, 

 at every hour in the day for eight days, without having had 

 an opportunity of seeing more of it above the sand than the 

 open mouth and reflected filaments; as if patiently waiting for 

 its prey. 



The largest example of this fish which I have seen was in 

 length two inches and three tenths, with a depth of three 

 tenths of an inch, exclusive of the fins; the body sharp at tie 

 tail, but less so at the head, as the generic name might lead 

 us to suppose; the body and head so transparent that the 

 inward structure can be discerned; and what renders this little 

 creature highly curious is the fact, that with a vertebral coluti.n 

 or backbone distinctly made out with its separate joints, there 

 is no separate skull, so what little appearance of brain there 

 is can only be compared to what is found in creatures that 

 have no vertebree; and especially to that very inferior class of 

 ringed animals which bear the name of Entozoa. The jointed 

 vertebrae in the Lancelet are continued forward on the head, 

 even to the point of the snout. The mouth is large and under 

 the head; where it does not lie across, as in other fishes, but 

 lengthwise; and when at rest its inward cavity contains the 

 lengthened filaments, of which ten were counted, but there may 

 be a couple more. They lie crossing each other within the 

 mouth except when in action; and when dead they usually 

 hang loosely outward. The number of lines which may be 

 judged to mark the number of joints in the backbone was 

 sixty; and between each of them and the next were five per- 

 pendicular rays of a fin, with two or three anterior to the first 



