N. Y ATS IT. 



63 



A visit to the collecting ground which is exposed at the time of 

 low water shows at once that no trace of Lingula can he detected 

 from the surface. The reason is probably as follows : the retreating 

 tide disturbs mud, so that the entrance of burrow is stopped up and 

 at this the animals retire deep in their burrows. This fact stands in 

 opposition to the observations of François and those of my friend Mr. 

 Namiyk who informs me that he was able at Bizen to find out the 

 specimens by three holes on the surface of mud. In the localities examin 

 ed by these observers, I think, the mud must be so hard or heavy that it 

 is not easily disturbed by the tide. On digging, however, specimens 

 are soon met with at a depth of about one foot. They show no sign of 

 attachment to either rock or stone but it is so firmly fixed to the hard 

 sandy mud that, when suddenly drawn out, the entire peduncle or its tip 

 is apt to be torn off and remain in the mud. On pulling out the 

 specimens we find that a bit of mud is usually encrusted at the tip of 

 the peduncle, and in some cases the latter is attached to a fragment of 

 bivalves. This stands in opposition to the description of Dall, which 

 runs as follows : " the true Langulas are almost always attached to a 

 fixed rock or stone, while Glottidia attaches itself, if at all, only when 

 adult, and usually to a very small pabble or bit of shell " (Beyer '8b - 

 p. 228). The tube-forming around the peduncle seldom takes place and is 

 not so usual a phenomenon as described by Morse. Nearer the shore 

 are usually found younger individuals. It seems that the free- 

 swimming life terminates in the shallows. The burrow is not 

 always vertical ; sometimes it is oblique or nearly horizontal, or 

 sometimes it is bent in the middle, the lower limb being vertical. There 

 are some cases in which two individuals are found in the same burrow, 

 but this must be regarded as accidental ; for in the first place their 

 power of locomotion is very limited, and secondly as fertilization takes 

 place in the open water it is of little advantage for them to dwell in 

 pairs. 



For the purpose of studying the cecology of Lingula I kept in the 

 autumn of last year, a number of individuals of various sizes in 



