654 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Comatulse and on Pentacrinus, BatJiycrinus, and Hhizocrinus, enable 

 him to confirm in almost every respect the investigations of Ludwig 

 on Antedon rosacea ; especial attention is, as may be supposed, given 

 to the nervous system. In the discussion on the characters of the 

 colouring matter, it is interesting to observe that pentacrinin was 

 found in Holopus ; one species of the new genus Metacrinus has a 

 different colouring matter, which is light pink when fresh. 



The seventh chapter deals with the habits of Crinoids and their 

 parasites ; the eighth with their geographical and bathymetrical dis- 

 tribution, the results of which are usefully arranged in tabular form. 



A characteristic of the work is the attention which is given to 

 palseontological discoveries, and the relations of the Neocrinoids to 

 the PalaBocrinoids. The following table shows the mutual homologies 

 of the principal plates in the actinal and abactinal systems of 

 Echinoderms. 



The following is the classification adopted : — 

 Phylum. Echinodermata. 

 Branch. Pelmatozoa. 

 Class 1. Crinoidea. 



„ 2. Cystidea. 



„ 3. Blastoidea. 



In the order Neocrinoidea we have descriptions of the several 



