372 W. C. M'lNTOSH ON BRITISH ANNELIDA. 



scientific accuracy in microscopic work. Thus the three forms Harmotho'e sihbaldii, 

 E. zetlandica, and H. macleodi would not readily strike the observer as specifically 

 diffei'ent from each other or //. imbricata. It is possible that the Pannenis Ijungmani 

 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 

 Polynoidae), the cilia on the scales, tentacle, antennae, 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 Polynoidse as opposite instead of alternate, yet he is one of the 

 best delineators of the group in modern times. The engraving of an accurate drawing 

 is often sufficient to alter the character of some of the minute points ; and it is not 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 Jeff'reys 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. CoUings, Prof. E. Ray Lankester, and Dr. Cooper gave 

 me some from Guernsey and Herm ; Prof. G. S. 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 Gxinther, 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. 



