372 W. C. M‘INTOSH ON BRITISH ANNELIDA. 
scientific accuracy in microscopic work. Thus the three forms Harmothoé sibbaldit, 
H. zetlandica, and H. macleodi would not readily strike the observer as specifically 
different from each other or H. imbricata. It is possible that the Parmenis ljungmani 
of Malmgren may refer to one of them; but the want of precision in description and 
figures makes it impossible to find out without an actual reexamination of the original 
specimen. A wide field also remains in regard to the sexual variations of the bristles ; 
but it will be easy to accomplish this matter if once the true character of each bristle 
is appreciated and accurately figured. Moreover, just as the bristles of a species show 
a tendency to adhere to the same type in all their characters (for instance, in the 
Polynoide), the cilia on the scales, tentacle, antennz, tentacular and dorsal cirri, and 
the form of the tips of the latter organs preserve a similar uniformity. 
Further, in delineating the structure of the Marine Annelids it is absolutely necessary 
to have an artist who is sensitively alive even to a tendency to variation in a character 
of a particular part; it is deficiency in this respect that makes the voluminous plates of 
many authors of little scientific value. It is well if the author himself uses his pencil ; 
for a mere artist, however skilful, almost always fails to appreciate the nice distinctions 
upon which so much depends. I have seen only one who fulfilled the requirements 
of science in this respect. Malmgren’s artist, for example, represents the spinous rows 
in the bristles of the Polynoide as opposite instead of alternate, yet he is one of the 
best delineators of the group in modem times. ‘The engraving of an accurate drawing 
is often sufficient to alter the character of some of the minute points; and it isnot to be 
supposed in the case of an inaccurate one that this process will improve the original. 
The collection from which the following descriptions are drawn up has been the 
result of many years’ labour. Amongst others, Dr. Gwyn Jeffreys most kindly handed 
over his valuable and extensive collections from Shetland, the Hebrides, and the west 
coast of Ireland; the late Dr. Baird sent specimens from Cornwall and other parts; 
Dr. Perceval Wright favoured me with the examination of the late Mr. Thompson's 
collections, as well as those found by himself on the west coast of Ireland; Mr. More 
likewise sent specimens collected in the latter region; and Dr. Carrington forwarded a 
collection from Southport ; Mrs. Collings, Prof. E. Ray Lankester, and Dr. Cooper gave 
me some from Guernsey and Herm; Prof. G. 8. Brady, those dredged on the coast of 
Durham; Dr. Howden, many from the deep water off Montrose; Dr. John Grieve 
from the Frith of Clyde; and Dr. Albert Giinther, Professors Ogilvie and Dickie, some 
from the North Sea; while Mr. Spence Bate and Mr. Rowe sent a collection with 
drawings from Plymouth and neighbourhood; and I am also much indebted to the 
late Dr. J. E. Gray, of the British Museum, and to the late Mr. G. R. Gray for their 
invariable courtesy in giving me every facility for examining the national collection 
of the Annelida; and to Mr. Smith and the other Assistants in the Zoological Depart- 
ment for their kind aid on many occasions. The British coast has been explored by 
myself at many points, from the Shetlands to the Channel Islands. 
