30 HISTORY OF THE SUBJECT. 



During the same year (1852) Dr. Max Miiller 1 gave an account of certain structures from 

 the proboscides of an unknown Meckelia and Alardus caudatas, which he termed bacillarv bodies, 

 and some of those from the first-mentioned form contained long urticating threads. These 

 bodies are the elements of the glandular papillae, and I have not as yet seen such (urticatus) 

 organs in the British species, although fine processes and mucus-threads occasionally project from 

 the summits of the papillae under pressure. 



In the zoological sketches of Dr. Max Schultze, published at this time, 2 the researches of 

 E. Desor on development are reviewed and corrected from observations on Nemertes olivacea, a 

 species which the author considers identical with Dr. Johnston's form {Lineus gesserensis). He 

 also issues a very important scheme for the arrangement of the Nemerteans, which scheme is 

 founded on the basis advanced by Dr. Johnston many years before, viz. the absence or presence 

 of stylets in the proboscis. It is as follows : 



Nemertinea. 



Central nervous system consisting of two ganglia on each side, an anterior and posterior, 

 which have two commissures, a superior and inferior, between which the proboscis passes. 



Anopla. Enopla. 



Proboscis without stylets. Proboscis with stylets. 



The ganglia united- at their anterior border by a long Anterior border of the ganglia rounded. The dorsal 



and slender dorsal commissure. The lateral nerve-trunk commissure in the form of a small band between the 



springing from the anterior portion of the anterior ganglion, dorsal surfaces of the ganglia. The lateral nerve-trunks 



so that the posterior end is rounded. The ventral com- forming a continuation of the posterior ganglia. The 



missure common to both ganglia. ventral commissure common to both ganglia. 



On each side of the head is a large and often very The long cephalic furrow absent ; but there are ciliated 



shallow furrow, having a small ciliated pit at the posterior pits, 

 end. 



Though his classification is by no means complete, it certainly marks a decided advance on 

 the schemes of his predecessors. 



Few modern naturalists have done more to advance our knowledge of the habits of these 

 unfamiliar forms than the late Sir John Graham Daly ell, whose patience and perseverance — not 

 devoid of intuitive skill — are worthy of all praise. In the second volume of his ' Powers of the 

 Creator' (1853)/ he describes about twenty British species. Several of these, however, refer to 

 different states of the same animal, but all can be readily identified with the exception of Fermi- 

 cuius crassus. He grouped the Nemerteans under three genera, viz. fourteen under Gordius, 

 five under Vermiculus, and one under Planaria. He thought they might be classified thus : — 

 (1) Those wanting specks or eyes; (2) those where specks of an indefinite number were 

 evidently present ; (3) those with two eyes ; and (4) those with four eyes. If this worthy 

 naturalist had lived to superintend the publication of the volume, several inaccuracies which had 

 been overlooked in his earlier notes would have been corrected, as, for instance, the remark under 



1 ' Observat. Anatom. de Vermibus quibusdam maritimis/ Berolini, 1852. 



2 ' Zeitsch. fur wiss. Zool./ Bd. iv, p. 179. 1852. 



3 ' The Powers of the Creator displayed in the Creation/ &c., vol. ii. London, 1853. 



