CONCLUSION. 605 



like members of the radiated division of animals. " Whilst 

 in many of their characters they approach the true Ascidians, 

 especially the unattached species of the genus Cynthia, in 

 others they indicate a relationship with the cirrhograde Echi- 

 nodermata. They present the remarkable positive anatomical 

 character of a union of mantle with test; so that there can 

 be little question of their right to be regarded as members 

 of a distinct family of Tunicata." * 



And now I bid you farewell. I have felt, as I proceeded, 

 a growing conviction of my incompetency for the task I had 

 too willingly undertaken ; but as you have followed, with 

 patient steps, the tedious way, so I may natter myself you 

 are now fitted to pursue the future course unassisted. The 

 last two letters have wearied you, and yet there was a pur- 

 pose in this strain upon your attention, for, when nicely 

 examined, you will find that the tabular views of the sys- 

 tems I have given you, with more or less minuteness of de- 

 tail, not only mark the successive stages in the history of 

 our subject, but introduce you to its masters, and familiarize 

 you with the names of the principal divisions of the Mollusca, 

 and with their leading characters. This, I have thought, was 

 to be best done by oft repetition under different phases ; and 

 without this familiar knowledge you cannot enter, with any 

 pleasure, on the perusal and use of the books that must 

 aid you onwards, and enable you to correct and supply what 

 is here erroneous or amiss. 



Be careful, in conclusion, to ride your hobby leisurely 

 and at a pleasurable pace. It is neither for you nor me to 

 devote our time to natural history : — it is to be your re- 

 creation. " Every man must and will have some relief from 

 his more severe pursuits," is an axiom I borrow from a wise 

 and good man ; and you do well to seek that relief in a study 

 that calls at one and the same time the head and heart into 

 healthful exercise. There is enough in Concho! ogy itself 

 and its collateral bearings, to put the mental faculties on the 

 stretch ; and the objects on which you are to work, in their 

 careful observation and research, cannot fail to give birth to 

 emotions and affections and impressions of a good and cheer- 

 ful kind. They are the creations of Omniscience ; and there 

 is no evil there ; — nay, you may safely look upon the species 

 your study brings under your notice as so many moral em- 

 blems to be unriddled by your skill. 



" When I consider Thy heavens, the work of Thy fingers, 

 the moon and the stars, which Thou hast ordained ; What is 



* Forbes and Hanlcy's Brit. Mollusca, i. 42. 



