LAND CRUSTACEANS. 77 



spondence with the diminisliing height of the cardiac division. Each of them grows gradually 

 broader from before backwards, and is expanded at its posterior end. The \entral surface 

 of the stomach, between the two inferolateral cardiac ossicles, is thickened on each side into 

 a plate of cartilaginous consistency. In the middle line these two plates are sundered by a 

 strip of thin chitin, in which lies a median ossicle having the shape of a dagger, placed 

 lengthwise with the blade forwards. The pennate ossicle, which is the more dorsal of the 

 two, bears internally a fringe of long hairs. 



Cardiopyloric valve (31, PI. III.). This has the form peculiar to the Pagurinea and Galatheinea ; 

 that is to say, it bears a V-shaped elevation composed of close-set lamellae not unlike the 

 ridges of a file. The lamellae are flexible and the point of the V is backwards. The whole 

 structure is known as the " median inferior tooth." 



Lateral cardiopyloric ossicles are wanting. 



Group 2. Auricular ossicles (15, PI. III.). A pair of stout troughs, running backwards and 

 inwards from the hinder ends of the inferolateral cardiac ossicles, on the ventral side of the 

 stomach. The hollow of the trough is towards the inside of the stomach, and the hind end 

 of each is expanded and less stout than its fore-part. There are no auricles. 



Anteroinferior pyloric ossicles. A semi-transparent, four sided, median plate with a triangular pro- 

 jection from the middle of its fore edge. Behind it, and separated from it by the inner 

 ends of the preampullar ossicles, are two small, semi-transparent, triangular plates, one on 

 each side of the middle line. 



Preampullar ossicles. Semi-transparent, transverse plates, just in front of the ampullae on the 

 floor of the pyloric division. 



Posterior subampu/lar ossicles (17, PI. III.). Stout transverse bars, one on each side just behind 

 the ampullae. Their inner ends are expanded and meet, but do not fuse. 



Group 3. Anterior pleuropyloric ossicles (18, PI. III.). Each of these starts at its hinder end 

 by a roughly triangular expansion, with the apex directed downward and forward. From 

 this apex proceeds a stout ridge on the side wall of the stomach, which, running forward, 

 ends by articulating with the ventral end of the subdentary. The lower side of the ridge 

 bears a triangular expansion. In the space between this ossicle and the pyloric, the wall of 

 the stomach is thickened to form a cartilaginous plate. 



Middle pleuropyloric ossicles (19, PI. III.). A slender horizontal rod, behind and below the pre- 

 ceding ossicle on each side. 



Posterior pleuropyloric ossicles (20, PI. III.). A short, curved bar, with the convexity forwards, 

 behind the middle pleuropyloric of each side. 



Anterior siibampullar ossicles (21, PI. III.). An elongated calcified strip, hollowed on the outer 

 surface, lying above the auricular ossicle of each side. 



Middle subampullar ossicles (22, PI. III.). Thickenings of irregular form, bearing to the ampullae 

 the same relation that the anterior subampullars do to the auricular ossicles. 



Group 4. Uropyloric ossicle (7, PI. III.). A broad median plate in the pyloric roof, with the 

 anterior edge very concave, and the anterior angles produced and strongly calcified. 



Mesopyloric ossicles. The anterior pair are wanting ; the hinder ones (23, PL III.) are present as 

 a small oval plate on each side, in front of the uropyloric and outside its produced fore 

 angles. 



