222 FUNCTIONS AND INSTINCTS. 



there are some that are instructed to form asso- 

 ciations, which yet are not united by any material 

 tie or common body, so as to be physically inse- 

 parable. Of this description are the Salpes, 1 

 or biphores, as the French call them. These 

 are phosphoric animals, so transparent that all 

 their internal organs and all their movements, 

 and even all the contents of their intestines, may 

 be distinctly seen. They are gelatinous like 

 the medusas and beroes, and like them dissolve 

 into water. Their organization, however, proves 

 them to be Tunicaries. Certain species of these 

 animals, in this respect unlike every other genus 

 of the animal kingdom, have the property of 

 uniting themselves together, not fortuitously and 

 irregularly, but from their birth and in a certain 

 undeviating order. Bosc observed the reunion 

 of the confederate Salpe* which he thus describes : 

 " Every individual is attached by its sides to 

 two others, the mouth of which is turned to the 

 same side ; and by the back also to two others, 

 when it is turned to the opposite side." In this 

 circumstance it presents an analogy to the 

 combs of the hive bee, in which each comb 

 consists of a double set of cells placed base to 

 base, with the mouths of each set looking oppo- 

 site ways, and the cells so placed that a third of 

 the base of three cells occupies the whole of one 



1 Salpa. ~ Salpa confcederata. 



