of the Fishery Board for Scotland. 63 



A large sand-eel, 7| inches in length, was lying along the dorsal region of 

 the abdominal cavity of a codling (March 11). It was thickly plastered 

 with hardened paste. Its tail was twisted round the urinary bladder. The 

 skin of the liver which had evidently been destroyed was attached to the 

 peritoneum as a thickened wall along the ventral part of the abdomen. 



Another codling had a very small sand-eel, 2| inches long, coiled up 

 at the anterior end of the abdominal cavity. The anterior third of the 

 fish was buried in the liver, and the liver had grown attached to the 

 peritoneum. 



A sand-eel was discovered in one saithe. It was adhering to the 

 abdominal wall. 



Fig. 47 is a drawing of an Hermit-Crab adhering to the internal surface 

 of the abdominal wall of a cod. Dr. T. Scott kindly identified the crab as 

 Eupagurus hernhardus. It is in perfect condition. The shell is clean, and 

 quite hard. It covered a stretch of 3 inches (7"5 cm.). One of its limbs 

 was in part covered with the white paste {ps.) and two were attached to the 

 peritoneum at {at.). The remainder of the body was free. The crab had 

 escaped from its Molluscan shell. Its chelae and one walking limb had 

 made impressions in the wall of the abdomen, that caused by the dactyl of 

 the second pereiopod, being |-inch (6 mm.) deep (a;.). A small strand of 

 white tissue was attached to the dactyl, but not to the peritoneum. Lying 

 between the pagurid and the wall of the abdomen were parts of the limbs of 

 a smaller Crustacean apparently Galathea {sp.), and also a thin-walled tube 

 quashed and torn. 



A nematode was found close to the hermit-crab. It was dead. It was 

 surrounded by small white concretions attached to connective tissue, and all 

 over its surface were similar white bodies (fig. 48). Under the microscope 

 it was seen that the concretions attached to the worm were under the 

 integument. They, in many cases, had the skin raised into a papilla over 

 them (fig. 50), indicating that they had probably been the larvse which were 

 trying to push their way out of the body of the parent. The larvse were 

 elongated bodies. 



Barrett* described a sand-eel lying on the liver and partly attached to it. 

 It was covered with a white coat which had become attached to the liver. 

 He suggests that the sand-eel may have escaped from the gut to the 

 abdominal cavity of the haddock by passing along a pyloric csecum. And 

 having once forced a passage to the blind extremity of such a csecum, either 

 it should force its way through the end, or that the dilated tube should 

 break off at some point, giving to the passenger a tight-fitting cuirass, and at 

 the same time setting it free in the abdominal cavity, there to die, and to 

 become encysted partly by pressure and partly by inflammatory adhesion in 

 some soft organ such as the liver. 



While the mode suggested by this author might be the actual method of 

 escape in certain cases, it nevertheless seems probable that if the sand-eel passed 

 while alive from the stomach into the gut, it would be able to rupture the 

 latter at any part. But the perforation of the alimentary canal is not due 

 alone to the eflfort of the sand-eel, as the last instance described above shows. 

 The hermit-crab, it seems evident, must have passed out by a perforation of 

 the stomach. It does not appear likely that it could have made its way 

 into the gut. 



It is therefore not necessarily the case that either the sand-eel or the 

 Eupagurus were the sole agents in causing the lesion which afforded them 

 exit. A weakened condition of the wail of the stomach (due to parasites or 

 disease) may have afibrded the sand-eel an opportunity of rupturing it. 



* " Note on the Liver of an Haddock in which a Sand-eel was Partly Embedded," 

 Third Anmial Report of the Fishery Board for Scotland for 1884, p. 70. 1885. 



