Some Notes on Alcippe lampas (Haxc.). 185 
annelids as was supposed by Darwin. AURrIvILLIUS explanation of 
the striae and holes as marks of the teeth of the mantle in the 
growing animal seems perfectly satisfactory. The slit and the “fan- 
shaped spot” are sometimes straight, but more commonly curved. 
The position of the animal in its burrow can be seen in Fig. 2. 
The animal taken out. 
By dissolving the shell in acid the animal can be freed. It 
consists of a body doubled up ventrally so as to bring the tail end 
opposite the mouth and of a surrounding sac-like mantle which 
opens anteriorly by a slit. The dorsal part of the mantle is 
developed into a disk and only here the body and the mantle are 
connected. The body consists of a head and a thorax. It is a 
difficult and unsatisfactory problem to make out the number of 
segments which have entered into the formation of the body. While 
the internal organisation and the study of sections does not help 
us much, certain lines which can be taken as marks for the seg- 
mentation appear regularly and can be made out even in cases 
where at first they seemed to be wholly absent, if the animal be 
treated and studied in a number of different ways e. g. first in 
elycerine, then in balsam, first unstained in transmitted and reflected 
light, then stained etc. The dark-ground illumination I have found 
especially useful in working out a good many details. 
The head proper which consists of a hood-like projection (“Kopf- 
zapfen”) and the region of the mouth and mouthparts is not sub- 
divided, that is to say the segments, how many there may have 
been, have fused completely. 
A difficult point is do determine the line between the head and 
the first thoracic segment. At some distance caudad from the mouth- 
parts we find a distinct line separating off as it seems a segment. 
This segment consists of a median and two bulging lateral portions. 
The latter contain what we have to consider as kidneys. Attached to this 
segment is a pair of biramous appendages, the so-called “mouth- 
cirri” or oral cirri (Fig. 8c and 12). As BERNDT points out these 
cannot very well be looked upon as maxillary palps. They are 
too far from the mouth for that, too independent. They must be 
regarded as the first pair of thoracic appendages and the above 
mentioned distinct line of separation I am inclined to take as the 
line between the head and the first thoracic segment (J in Fig. 8). 
On the dorsal side I find a line a little caudad from the two 
