TEALTA TUBERCULATA (COOKS). 207 



tacle is perforated, and wlien a specimen is taken out of water and 

 contracts forcibly, water is forced out of tlie terminal pores of the 

 tentacles in streams with some force. 



The column is of a yellowish-grey colour with scattered patches 

 of red. It is closely beset with large bladder-like warts, which are 

 arranged in vertical rows in close proximity to one another. The 

 largest of these warts are on the margin of the column, while near 

 the base they get smaller and gradually disappear. Each wart has 

 from two to four white patches which are probably glandular. The 

 warts have the power, probably due to these glandular patches, of 

 attaching pebbles or sand to themselves, and to such objects they 

 adhere with considerable tenacity, but this property is not often 

 exercised in the natural condition, the surface of the column being 

 almost always bare. 



The base is usually expanded considerably beyond the column 

 when there is room for it ; when an animal on a somewhat small 

 shell is left undisturbed in an aquarium the base soon extends on to 

 neighbouring surfaces. 



The tentacles are strongly retractile, that is, they can be con- 

 tracted to a very small size towards their bases, and the margin of 

 the column can be contracted so as completely to cover the tentacles 

 and disc. When the animal is much irritated after the tentacles 

 and disc have been retracted and covered by the column, the animal 

 continues to contract and expel water from its interior until it 

 becomes quite flat so that the walls of the column form a disc almost 

 parallel to the base. 



The principal peculiarities of the species consist in the number 

 and arrangement of the tentacles. The primary tentacles, which as 

 already mentioned are conspicuously distinguished from the rest by 

 white bands enclosing their bases, are ten in number. These pro- 

 bably consist of two cycles of five, but there is nothing in the adult 

 to indicate this. Having recognised these primary tentacles it is 

 not diifficult in the living animal to ascertain the arrangement of the 

 other tentacles, in the space between any two of the primaries. It 

 is found that in any specimen some of the intervals between two 

 primaries possess a regular normal arrangement of other tentacles ; 

 this normal arrangement is seen in all the intervals on the right 

 hand side in fig. 1. The normal arrangement consists in the suc- 

 cessive subdivision of the space by tentacles, first into two halves, 

 then into four parts, then into eight, then into sixteen. That is to 

 say between the two primaries there is a tentacle of the second 

 cycle with a pair of mesenteries corresponding to it ; then on each 

 side of this tentacle, 6, there is a tentacle, c, of the third cycle, with 

 a pair of mesenteries ; then in the four spaces thus separated there 



