VOL. XXV.] PHILOSOPHICAL TRANSACTIONS. 31/ 



make use of it: and we even discovered at tiie end of each of the scabbards 

 three teeth projecting out, which I judge is for no other end than to shut 

 within one another. 



Fig. 11, pi. 9, exhibits the several parts of this machine: lm shows one 

 half of the scabbard, with its cavity, the teeth like saws, and the 3 teeth at 

 the extremity m : no represents the other part of the sheath, likewise furnished 

 with the same sort of teeth; and qp is the sting itself, placed between the two 

 parts of the scabbard, where p represents the little orifice or hole in it. Now 

 if we suppose that each of the parts of this sheath, as also the sting itself, are 

 furnished with divers muscles and fibres, necessary to produce all the motions 

 that belong to them, they may be deemed large instruments, in comparison of 

 those muscles that produce their motion : but then if we extend our thoughts 

 to those animalcula that are many million times smaller than a flea, and con- 

 sider also their respective instruments for motion, &c. we must be lost in 

 amazement at the thought. 



Description of the Pediculus Ceti, &c. By Sir Robert Sibbald. N° 308, 



p. 2314. 



The pediculus ceti* is the balanus balaenae cuidam oceani septentrionalis 

 adherens, Lister Hist. Conchyl. Bocconi, who was the first that mentioned 

 it, in his Recherches et Observations Naturelles; but his description of the 

 shell is better than the figure he gives. The shell approaches to a sexangular 

 figure, and consists of one valve, in which it differs from all the balani I have 

 seen; it has no spiral circumvolutions, nor apex, but it opens at both ends; 

 the orifice of the upper end is narrower, and through it the animal puts forth 

 its cirrhi or brachia; the orifice of the lower end is much broader, and the 

 animal is lodged in it. The lower is divided, as Boccone observes, into 18 

 lines, which are raised, 12 of them being simple and straight, and the other 

 6 branched: these last are so placed; that two straight lines are between each 

 of them: and there is a cavity between all of them, in which the cirrhi or arms 

 of the animal are probably placed, though in this subject they stood in the 

 middle of the upper part of the shell, with their ends contracted; for the upper 

 orifice is deeper than the lower. There is an opening from the under part 

 to the upper, by which these cirrhi mount from the head of the animal. 

 The orifice of the upper part is narrow below, but wide in the middle, and 

 then again contracts somewhat. The body of the shell is convex, and has 6 

 divisions, each consisting of 4 protuberant tubes; which are narrower at the 



>vi i .. * Lepas Diadema. Lin. r ,.- <. 



