160 MARINE FAUNA OF ST. ANDREWS. 



sented by a narrow pedicle. The fourth pair lias a narrow 

 shield turned over at the free edge, and, instead of the two 

 narrow spikes below, there is a flattened organ which forks 

 into a narrow and a broad flap at the tip. The fifth pair has 

 its inner division broad and flattened, and its outer small, 

 but widened at the tip ; the median division has a very 

 regular arrangement of bristles at its tip, which points or 

 slopes inwards. 



The parasitic Peltogasti r paguri frequently occurs on the 

 abdomen. 



Pagurus cuanensis, Thompson ; Bell, <>/>. cit. p. 178. 

 Occasionally from deep water. 



Pagurus ultdianus, Thompson (?) ; Bell, op. cit. p. 180. 

 St. Andrews Museum. I cannot speak with certainty of 

 this form. 



Pagurus kevis, Thompson ; Bell, op. cit. p. 184. 

 Occasionally in the stomach of the haddock. 



Fam. Porcellanidae. 



Genus PORCELLANA, Lamarck. 



Porcellana platych les } IYnn. ; Bell, op. cit. p. 190. 



Abundant under stones between tide-marks, especially in 

 runlets, and on muddy ground. A group of young forms of 

 some size may sometimes be seen in company with their 

 parents. 



The first pair of foot-jaws have their two terminal segments 

 furnished with the longest hairs (proportionally) yet met with 

 in the local forms. The hairs have a double row of spikes, 

 diminishing towards base and tip, and ceasing before arriving 

 at the end of the hair, which has very fine linear serrations. 

 The external division has a powerful triangular, and some- 

 what tapering, lower segment, ami a delicate appendage fringed 

 with a brush of spiked hairs at the tip. The second pair has 



