2 Transactions of the Society. 



species dried much more quickly than others. It not being con- 

 venient to mount them at once, when living on the yacht, they were 

 well covered over with Canada balsam, which was afterwards dis- 

 solved oft' by benzol. Keeping them thus for a time has the ad- 

 vantage of showing whether the salt has been well removed ; but they 

 should not be kept too long, or they may become worthless. They 

 were then mounted in balsam under thin glass covers, in cells made 

 of thin glass strips. Though they have now been kept for above 

 two years, they have undergone no further change. When thus 

 mounted they are not only permanently preserved, but, being made 

 comparatively thin, flat, and transparent, the structure is seen far 

 better than when the animals are alive or recently dead. After 

 having been kept in alcohol or diluted formalin, they are not only 

 made more opaque, but the blood is so altered and lost that the ves- 

 sels become almost or quite invisible. When kept in strong glycerin,, 

 though the natural red colour is somewhat preserved, it is only the 

 larger vessels that are seen to advantage. Though, as I thought,, 

 treated in the same way, yet, for unexplained reasons, some specimens 

 turned out very bad. The character and arrangement of the vessels- 

 can be studied to great advantage, and is seen to be strikingly dif- 

 ferent in different species and genera. It is, however, very difficult to 

 prepare specimens so as to show the structures equally well all over. 

 Some kinds of worms are very easily injured in collecting, and though 

 the injury may be invisible, it may cause decomposition to occur 

 locally, before the specimen is dry, and the small and very delicate 

 blood-vessels are lost ; though, in other parts not so injured even the 

 small capillaries are quite distinct. 



Though it seems to me undesirable to describe the detail, yet it 

 may be well to give a general summary of the characteristic features 

 of the blood-vessels in the case of a few genera. There are very con- 

 siderable differences in different specimens of the same species, accord- 

 ing to their state of development, and apparently also according to the 

 circumstances in which thev have lived. The relative amount of 

 blood-vessels varies enormously in different localities, and at different 

 times of the year. In almost all cases there is much difference as we 

 pass from the head to the tail. 



Cirratulus. — A characteristic feature of this worm is the presence 

 of so many large vessels passing to the cirri from the main longitudinal 

 vessels, which latter are contracted and enlarged in each joint of the 

 body. Where the cirri are most numerous, the blood-vessels seem to 

 occupy fully one-half of the area in mounted specimens. Between 

 the lateral vessels are numerous branching capillaries, which are 

 much most numerous over the intestine. The hooked character 

 of some of the larger lateral vessels is also a striking feature. 

 Towards the middle of the worm, where the cirri are few in number, 

 the vessels of the intestine are so small and numerous that they can- 

 not well be seen separately, but give rise to a general red colour. 



