HUXLEY, ON THE MOUTH OF THE SCORPION. 251 



of past and present times, it is a remarkable circumstance 

 that no exact account of the structure of the commence- 

 ment of its alimentary canal is to be met with, at least so 

 far as my knowledge extends. Meckel (' Beitr'age zur 

 Vergleichenden Anatomie/ Band i, Heft 2, 1809), as might 

 be expected from the fact that his dissections were per- 

 formed without the aid of even a magnifier (page 106), takes 

 no particular notice of the small and delicate parts in question. 

 Treviranus {' Bau der Arachniden/ 1812) is equally silent as to 

 this important portion of the economy of the scorpion; and even 

 the accurate Johannes Midler, in the essay entitled " Beitrage 

 zur Anatomie des Scorpions" (Meckel's c Archiv.,' 1828), 

 which threw so much new light upon the organization of this 

 animal, although he saw more than either his predecessors 

 or his successors have done, did not probe the matter to 

 the bottom. In describing the alimentary canal, he merely 

 says : — " The pharynx which arises in front of the brain, 

 upon a particular, strongly excavated, portion of the skeleton, 

 is much wider than the rest of the intestine, and resembles a 

 vesicle. The oesophagus is very delicatewhere it proceeds from 

 this vesicle, rises between the very stout nerves for the ehelae, 

 above the brain (which lies behind the pharynx), and passes 

 over the saddle-shaped upper excavation of the internal 

 thoracic skeleton, whilst the spinal cord and the posterior 

 cerebral nerves pass through the opening of the same 

 skeleton." 



Even the elaborate and beautifully illustrated memoir on 

 the organization of Scorpio occitanus, published by M. 

 Blanchard, a couple of years ago,* does not furnish the in- 

 quirer with either definite or accurate information on this 

 point. At page 19, I find under the head of " mouth :" 



"In the scorpion there exists only a single buccal piece properly so called; 

 it is inserted in the median line above (au-dessus) the mouth, just below the 

 chelicerse (antennes pinces), and wedged in, so to speak, between the foot-jaws. 

 Jt is a little flexible appendage, thinner towards its extremity, sensibly 

 dilated Literally, convex above, and beset, chiefly at the end, with fine and 

 silky hairs. This piece presents two apodemata (apodemes d' insertion), 

 which diverge greatly from one another. 



" One finds a certain difficulty in positively determining the nature of the 

 single buccal appendage of the scorpion. It is impossible to regard it as 

 the analogue of the labrum (levre superieure) of insects. The labrum is one 

 of those pieces which abort most completely in the arachnida. Besides, in 

 all articulata, this labrum receives nerves which arise from the cerebral 

 ganglia. It is different with the buccal appendage of the scorpion ; its 

 nerves arise from the anterior part of the subcesophageal ganglia, exactly 



* The livraisons of M. Blanchard's work are unfortunately published 

 without dates. 



