2o6 Copepoda living as Parasites or Messmates. [Sess. 



by my son is very simple. All the hermits brought up in the 

 dredge or trawl are, with their shells, dropped into a jar con- 

 taining methylated spirit, and left till there is sufficient leisure 

 to wash thoroughly both the crab and the shell. The sedi- 

 ment in the bottom of the jar is afterwards collected and 

 examined. Simaristis does not appear to be very plentiful. 



6. Copepoda that are associated with various species of Mollusca. 

 — Quite a number of copepods are known which, in one way or 

 another, are associated with Mollusca ; a few of these will now 

 be referred to. The large clam-shell {Pecten maximus) and the 

 smaller (P. opcrcidaris) — the latter very common in some parts 

 of the Forth estuary — a£ford accommodation for probably more 

 than one copepod. The name of the one best known to me, 

 however, is Herrmannella maxivia (I. C. Thompson). This is 

 one of the species discovered by the late I. C. Thompson of 

 Liverpool. It was first observed in Pecten maadmus, and was 

 described as a Lichomolgus ; but in the rearranging of genera 

 and species another place had to be found for it, and so it has 

 for the present been transferred to the genus Herrmannella. 

 It is just possible, however, that it will not get leave to remain 

 there, but may have to seek another home. 



Herrmannella rostrata Canu. — There used to be, and no 

 doubt there still is, a large cockle-bed between Cramond and 

 Cramond Island. The cockles there are the common edible 

 species {Cardium cdule). A considerable proportion of the speci- 

 mens are small, but fairly large ones may be obtained. It was 

 in the larger specimens that the copepod mentioned above was 

 most frequently observed, as many as sixteen specimens having 

 been found in a single cockle. In these researches two methods 

 were employed. The more exact of the two was to open the 

 shell by inserting a knife and cutting the muscles, meanwhile 

 holding the shell so that one at least of the valves would 

 retain a portion of the fluid. If copepods were present, they 

 might then be seen swimming about in this diminutive lake. The 

 second and quicker method was to put a number of shells into 

 a basin, and then pour in methylated spirit sufficient to cover 

 them — having previcrtisly opened the shells to allow the spirit 

 to enter freely. The sediment could then be examined, and 

 the copepods picked out. 



We found this copepod in 1892, and, believing it to be a 



