456 PROCEEDINGS OF THE ACADEMY OF [Sept.. 



califoi Nothing further is known concerning their mode of 



life. Leploplana inquieta was dredged on one occasion in water 



about six fathoms in depth; it is usually concealed in the burrows 



coring mollusks (Penitella penita), and when dislodged 



pr< to be an active, restless species incapable of living in 



ptivity. Leploplana saxicola is peculiar in that it inhabits 



small, elevated tide pools whose waters are changed only during 



rough weather, when they are submerged in the dashing surf. A 



growth of algae (Cladophora) frequently lines such pools, and in 



its i'eltwork this species may be found in abundance, living upon 



small mollusks, Crustacea, and an occasional rhabdocele, whose 



remains have been found in the digestive tract. The species of 



Eurylepla and Amblycereus are usually found in the rhizoids of the 



brown kelp (Macrocyslis pyrijera). Amblycereus luteus is an active 



swimmer, progressing by means of wave-like undulations of the 



margins of the body. Most of the remaining species described in 



the following pages were secured from collections made by students 



attending the seaside laboratory of Stanford University at Pacific 



drove and were gathered at low tide, though we have no accurate, 



information concerning their exact habitat or mode of life. 



The food of several of the species consists largely of minute organ- 

 isms in the plankton or small, strictly littoral species. In their 

 digestive tracts have been found small spores, unicellular plants, 

 especially diatoms, numerous sponge spicules, remains of amphipods 

 and isopods, multitudes of Sabella larvae, small annelids and the 

 radulse of gastropod mollusks. These substances frequently impart 

 a characteristic color to the animal, and several of the more trans- 

 parent species derive much of their apparent outward tint to materials 

 in the digestive tract, as is shown by keeping such animals in cap- 

 tivity without food until that already eaten has digested, when their 

 true color becomes apparent. 



In the fixation of these animals the ordinary methods were" em- 

 ployed. Lang's formula particularly was used with good results, 

 but was slightly inferior to another solution that we devised during 

 the course of our study. To 4 parts of a saturated solution of corro- 

 sive sublimate 1 part of formaldehyde was added, and 100 parts of 

 this mixture were combined with 5 parts of glacial acetic acid. The 

 solution was used hot and usually was poured over the specimen, 

 though active, highly contractile individuals were often imprisoned 

 1 >etween two microscope slides lightly held together. When this last- 

 led device was employed, the specimen usually remained attached 



