INTRODUCTION. 



One of the objects of the present Catalogue is to supply the students 

 of the British marine fauna with a handbook by means of which, it 

 is hoped, they may be able to recognize such members of the very 

 well-defined group of Echinoderma as they may collect in their 

 expeditions to the sea- shore or in more extended dredging excur- 

 sions. The study of Starfishes and Sea-Urchins, which may be 

 taken as the English for Echinoderma, has long been a favourite 

 pursuit with British naturalists, owing largely to the peculiar 

 charm of one of the most popular of Mr. Van Voorst's well-known 

 3eries, Professor Edward Eorbes's ' British Starfishes.' So far as 

 that volume is the work of an enthusiastic and experienced field- 

 naturalist, it does and will always hold the chief place in the regard 

 of every lover of Natural History, and what follows here must not 

 be thought of as attempting to oust Forbes's book from its position. 

 Unfortunately, however, the progress of zoological science is still 

 marked by considerable changes in nomenclature, and from this 

 point of view Forbes's work has long been out of date. On the 

 other hand progress is, fortunately, marked by the discovery of new 

 or exotic species in our seas, and by the union of forms which have 

 been incorrectly regarded as specifically distinct. While Forbes 

 enumerated (omitting the Gephyrea, which are not now regarded as 

 Echinoderms) fifty-five species, there are contained in the present 

 Catalogue one hundred and thirty-two ; but of the fifty-five, eight 

 are here regarded as synonyms, one (Arachnoides placenta) is expelled 

 from the list, and Psotinus brevis remains as great a mystery to me 

 as to many others. The great increase in the number of species is 

 due, chiefly, to the dredgings at depths which Forbes believed to be 

 azoic. The inclusion of species known from the Faeroe Channel, which 



