<;i_) mr. E. R. LANKESTER ON SOxME LOWER ANNELIDS. 



son, demonstrator of Anatomy at the University Museum, Oxford, in a bottle of water 

 from tin- riv.r, in which they made their appearance during May. The largest spe- 

 cimens I observed were nearly } inch in length; nearly all were producing zooids by 



pi fcerior cm matron. 



The outline of the worm is very loose and uncertain, the body flowing in various 

 directions in a very strange liquid fashion, the alimentary tube within also exhibiting 

 t!ie most five and independent movements, as though not bound in any way to the 

 integument or body-wall. Tin; prostomium is most remarkably developed, broad and 



Hat, reaching far in front of the mouth, and abundantly ciliated. The seta?, or 

 bristles, are very fine and hair-like; the bundles are in a double series on each side of 

 the body, two dorso-lateral bundles and two ventral bundles to each segment. The 

 body is not distinctly segmented, but shows more approach to annulation than in 

 Cli<rlo(f, iter; apparently a head and six segments constitute the individual. There are 

 no cephalic bristle-bundles like those of Chcetogaster \ and so, in estimating the indivi- 

 dual, we reckon a head, and a segment for each set of bristle-bundles. The zooids are 



produced by the constant tendency of the sixth segment to bud, or the failure at this 

 point of the longitudinal force which counteracts the force of growth in an anterior 

 direction and formation of a head. The prostomium of a zooid when formed, projects 

 in a very strange way from the zooid, as seen in the figure (fig. 5). I have only seen 

 chains of two zooids with portions of two others incomplete behind them. 



The integument is ciliated on the ventral surface of the prostomium, and nowhere else. 

 Its most remarkable feature is found in the oval vesicles which are scattered all about 



like the clear resides in Ck 



but which are of a clear blood-red 



colour, whence the name JEolosoma. I have not succeeded in bringing this colour 



under the micro-spectroscope. 



The fluid in the system of vessels is of a pinkish colour. There is the usual large 

 contractile dorsal stem ; and the ventral stem appears to break up on the intestine. 



The perk scenn I fluid presents very few granules or corpuscles. The mouth opens into 

 in alimentary tract which is most densely covered with coarse, active cilia throughout 

 it - length ; the fo. >d appears to be brought in, to a very great extent, by the action of these 

 cilia and those on the broad expanded lip or prostomium. The phary nx is short and 

 mnscnlar; the (Esophagus is a long tube folded or twisted on itself, and opens into the 

 stomach or into tine, which commences with the third segment, and runs through the 

 body, hanging very loosely by a few muscular septa, becoming constricted and narrow 



at the end of the sixth segment. There is in each segment except the head a large 

 well-developed * mention, winch appears as a tortuous, coiled canal, densely within. 

 Ihe nervous system is very obscure. 



I, the water, with the' JkUmma, I observed some small creatures whieh I take to be 

 the young form hatched from the egg. In fig. 4, one of these is drawn. There is the 



of JEolosoma 



te«,,mentarv v, ,lo, or po„ M fat- lim ,, s . He has been nmuceesrful in detectin 



and observes that D Telekom's fin-m™ n f *u :j_v ueiecun. 



tide, • sehr schomatisel, " n M 1 1 "T " 7 *° T^ ^^ " ° tW "V* that «"» must be ' 



* ' ■ Dr. Magg, has also lately pnblished a memoir at Milan, which I have failed to see. 







