32 ME. M. LAURIE ON" THE 



organ has been described in Galeodes by Croneberg *. Bruce 

 considers it to be a sense-organ, while Croneberg compares it with 

 the paired processes in Asellus, which probably represent the 

 remains of the shell. 



Bruce has described a cellular amnion round his embryos. Of 

 this I can find no distinct trace, but it may have atrophied at an 

 earlier stage. 



The embryo appears, however, to cast off at least one cuticle 

 in the course of development. This cuticle follows roughly the 

 outlines of the body, and seems to be cast off during the later 

 stages of the process of reversion, as there are cross partitions 

 between the layer covering the cephalothorax and that over the 

 abdomen. Between these two layers, and therefore outside this 

 cuticle, there are traces in one of my embryos of a thin- walled sae 

 with granular contents, but whether this is the remains of a still 

 earlier cuticle or not I am unable to say. 



The Gut (PI. V. fig. 21). 



The gut is composed, as usual, of three well-marked divisions — 

 Stomodseum, Mesenteron, and Proctodseum. The stomodgeum is 

 a narrow tube extending from the mouth to a little behind the 

 brain. In front of the brain there are attached to it powerful 

 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 — i. e. the part lying in the 

 cephalothorax — is dilated to form a sorb of stomach as in Tliely- 

 pJionus. The dilatation seems to take the form of a single pair 

 of lateral outgrowths, very similar at this stage to the lobes of 

 the " liver." A small median ventral outgrowth is also present^ 

 and reminds one of the median processes in Thelyphonus . The 

 middle part of the mesenteron is very short, only extending as 

 far back as the fourth free segment. There are four pairs of 

 diverticula forming the so-called liver, of which the first three 

 divide almost immediately into a dorsal and ventral portion. 

 The " liver " lobes of these three are small and well defined, the 

 * Croneberg, Zool. Anz. 10 Jahrg. 1887. 



