1902.] ANATOMY OF THE PEDIPALPI. 187 



on the outer and posterior side of tlie first apoj)hysis between it 

 and the second, which resiilts apparently from its fission and is 

 unrepresented in Thelyplionus and the Spiders, although, so far 

 as the diverticula are concerned, it coi-responds to the second 

 apophysis in these groups, inasmuch as it juts up between the 

 diverticula which extend towards the thii'd and foui'th appendages 

 (first and second pairs of legs). The third apophysis, the 

 homologue of the second in the other groups, instead of rising 

 behind the first diverticulum, emerges behind the second with 

 the anterior branch of the fourth, while the posterior branch of the 

 fourth (numerically the fifth) similarly appears behind the third 

 diverticulum in company with the sixth apophysis. 



Or if, for the sake of clearness, we assume that there were 

 originally five diverticula representing the five postoral somites, 

 and four apophyses belonging to the first four of these somites, 

 and that the diverticidum passed in front of the apophysis in each 

 somite, as is the case in the Spiders and Thelyphonidse ; and 

 further, if we assume that the two additional apophyses in 

 Phrynus have been dei'ived by fission from those of the first and 

 third postoral somites, the differences between Phrynus and the 

 others with regard to the ai-rangement of diverticula and apophyses 

 may be briefly stated as follows : — The apophysis of the second 

 postoral somite has moved backwards behind the diverticulum of 

 the third postoral somite, its place behind its appropiiate diver- 

 ticulum being taken by the outer branch of the first apophysis, 

 and the extra branch of the third apophysis has similarly shifted 

 back behind the diverticulum of the fourth postoral somite. 



Laurie describes the stomodfeum as "a nari-ow tube extending 

 from the mouth to a little behind the brain. In front of the 

 brain there are attached to it powei'ful muscles running dorsally 

 to be inserted in the carapace behind the median eyes. Lateral 

 muscles are also present in this region, which no doubt has a 

 suctorial function, though there is no sign of any dilatation 

 to form a sucking-stomach. Close behind the brain, and just in 

 front of the junction between the stomodseum and the mesenteron, 

 are inserted some more muscles which also pass dorsally to the 

 carapace. The anterior part of the mesenteron is dilated to form 

 a sort of stomach as in Thelyphonus. The dilatation seems to 

 take the form of a single pair of lateral outgrowths, very similar 

 at this [embryonic] stage to those of the ' liver.' A small median 

 ventral outgrowth is also present, and reminds one of the median 

 processes in Thelyjjhonus." ^ 



These observations were based upon embryos. The only 

 discrepancy between this description and that given above of the 

 adult, is the attachment of the muscles of the pre-cerebral sucker 

 to the under surface of the carapace. 



Blanchard's description, based upon the adult, makes no mention 

 of the muscle which passes dorsally from the pre-cerebral sucker 



1 Jouni. Linn. Soc, Zool. xxv. p. 32 (1894). 



