42 CALIFORNIA ACADEMY OF SCIENCES. 



such a group, as is the practice of systematists in some 

 quarters, with a large probability that the literature of the 

 subject will thereby be permanently befogged for future 

 students. 



At extreme low tide, the species is abundant at Pacific 

 Grove, though rather less so than numerous other 

 species of compound Tunicates with which it is associated. 

 It grows upon rocks, sea weeds, larger sertularian 

 hydroids and other common objects of the shore, but 

 particularly on another Tunicate, a large, undetermined 

 species of Clavehna, that is common here. To what 

 depths it extends I do not know. None have been taken 

 by the dredge, for our dredging at Monterey was con- 

 fined to sandy bottoms where the Perophora would not 

 be likely to occur to any considerable extent. 



The colonies in which the ascidiozooids are most com- 

 pletely embedded in the common testicular mass and are 

 most crowded, are found on such objects as present a 

 rather even surface, over which they ma}^ spread. Thus 

 in many instances the large individuals, an inch and more 

 in length, of the Clavelina, already mentioned, are found 

 to be almost completely covered over by a coating of the 

 Perophora colony. 



Fig. 2, pi. i, represents a small portion of a colony of this 

 kind, twice its natural size, situated on a twig of seaweed. 

 Only the basal portion of the colony is figured, the pur- 

 pose being to show not only the crowded condition of the 

 zooids, but also the fact that a few individuals (I. zo.) of 

 the colony are isolated. It should be mentioned, how- 

 ever, that in no case have I found one of these isolated 

 zooids, in a colony of this kind, raised at all from the 

 stolon on a peduncle, as is the case in some of the species 

 of the genus. Fig. 4, pi. i, represents the margin of another 

 colony of the same kind on a leaf of eel grass. The con- 



