Oatty Marine Laboratory^ St. Andrews. 117 



than a quarter of a century afterwards (it may be with a new 

 and imposing title) in foreign papers before they can be 

 utilized by the modern text-book in our country. With all 

 deference to my friend Prof. Hubrecht and to Dr. Burger and 

 other able observers, I see no valid reason for altering the old, 

 yet simple and satisfactory, classsiiication indicated by 

 Dr. George Johnston and used by Max Schultze, resting 

 securely, as it does, on structural foundations. No student can 

 misunderstand the fact that the proboscis of the Nemerteans 

 is either armed (Enopla) or unarmed (Anopla). None will 

 mistake those which fall under the first group. Under the 

 second group are three great divisions (be they suborders 

 or families is immaterial), viz. the Lineid«, Carinellidge, and 

 Cephalotrichidse, and as each bears the name of its type, the 

 arrangement also has the merit of simplicity and perspicuity. 

 When systems of classification rest on data that are unsound 

 or are liable to be misunderstood, few will gainsay the 

 propriety of making a change ; but when new and confusing 

 names simply cover the old yet unassailable facts, the process 

 seems to be both unnecessary and perplexing, as well as one 

 that tends in no way to the advancement of zoology. 



EXPLANATION OF PLATE n. 



Fig. 1. Larval Clione, -w-ith three rings of cilia, armature of odontophore 

 and lateral sacs, and an otocyst. 3rd Nov., 1897. x 50. 



Fig. 2. A younger fonu of the same species, with a row of globules in 

 front of the median ciliated ring. 3rd Nov., 1897. x 50. 



Fig. 3. A somewhat older and more elongated form of same date, x 50. 



Fig. 4. A more advanced stage of the same species with bihd anterior 

 region. 18th Feb., 1898. X 60. 



Fig. 5. The same viewed laterally so as to show the middle and poste- 

 rior lobes of the foot, a and b. X 60. 



Fig. 6. An older example of Clione limacina with lateral fins. X 40. 



Fig. 7. Teeth of the odontophore and lateral sacs in situ of fig. 1 

 (•Srd Nov., 1897) under compression. In nature they were 

 placed widely apart, but the blank has been omitted to save 

 space. X 250. 



Fig. 8. Bipinnaria asterigera, Sars, showing the asterid from the side, 

 with the gullet and intestine passing to the Bipinnaria. The 

 ridges and grooves of the preoral lobe are fairly evident. 

 Enlarged under a lens. 



Fig. 9. View of another example exhibiting the ambulacral feet of the 

 asterid. Similarly enlarged. 



Fig. 10. Specimen having a more complete series of arms and ciliated 

 ridges. Enlarged under a lens. 



Fig. 11. Acute spine from the first scale of Lepidonotus Wahlbergi, Kbo^. 

 X 230. 



Fig. 12. Capstan-like tubercle — minutely spinous — from the first scale of 

 Lepidonottis clava, Mont. X 230. 



