498 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



continuously to thrust the body backward for a distance equal to 0.25 to 0.50 its 

 diameter with each thrust of the prod. 



Cytolysis of the Ixxly ensued about an hour after autotomy and disappear- 

 ance of the prod. The approach of this catastrophe is first indicated by the 

 rapid formation of minute liquid spherules extruded simultaneously on all 

 sides of the body, apparently by the discharge of the fluid aeciunulating in 

 the peripheral vacuoles. This is speedily followed by the rupture of the 

 peripheral pellicle, the outpouring of the contents of the body and its rapid 

 and complete liquefaction. The reversal of the living substance from a gel to 

 a sol is complete and takes place with remarkable rapidity, the pellicle disap- 

 pearing as rapidly as the cell contents (text fig. TT, 8). In the last vestiges 

 of the granular cytoplasm the short transverse flagellum was observed with 

 active undulating contractions still passing through it. The organs which resist 

 solution longest are the nucleus and the ocellus. The nucleus gradually wastes 

 away, the peripheral clear zone and chromatin network becoming more distinct 

 before final disruption and solution. It appears to be a more resistant gel than 

 the surrounding cytoxdasm. 



The cytolysis of the ocellus (figs. TT, 4-7) when released l)y solution of the 

 surrounding cji:oplasm proceeds slowly to a complete disappearance in about 

 twenty minutes. The lens elongates, becomes surroiuided by a clear zone, pre- 

 sumably a sol, formed from its own substance, is released from the pigment 

 mass in which it is embedded and rounds up into a sphere which gradually 

 wastes away as the zone of solution about it becomes indistinct. The brilliant 

 red. central core flows out from the center of the melanosome (figs. TT, -1—7) 

 and rounds up in several spherules. The melanosome also rounds up and the 

 two colored masses -^-ery gradually waste away witliout imparting any recog- 

 nizable tint to the surrounding water. 



Occurrence. — Two specimens of this species were taken July 12, 1917. with 

 a No. 25 net, in a haul 6 miles off La Jolla, California, in a liaul from 80 meters 

 to the surface and in a siirface temperature of 20° C. The same day another 

 individual was noted in a haul made on the previous day and kept in the labor- 

 atory over night. This was made at a distance of 4 miles off La Jolla, from 80 

 meters to the surface and in a surface temperature of 19?8 C. 



CoMPARisoxs. — E. extrndens is the most highly specialized and widely 

 divergent member of the subgenus Erijfln'opsiis, and is nearest of all its members 

 to the subgenus Polijopsidella. The structural features indicating this are the 

 detached pigment j)articles, the marked internal stratification of the lens sug- 

 gesting a transition to or from the compound condition, the reduction in the 

 size of the tentacular recess, and the oblique tenta<-le or prod. These features 

 are not mdike the divided lens of E. hispida, the scattered pigment of E. ]abn(i)i. 

 and the reduced recess and oblique prod of E. scarlatiiuu all included in Poli/- 

 opsideJla. Since, however, its lens is not externally divided into separate lobes, 

 E. extrudens is not placed in the subgenus with compound ocellus, liut it is 



