486 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



therein, it seems imperative to conclude that Pavillard's (1905) form is not 

 that of Hertwig (1884), but a distinct species which we call Erijthropsis pavil- 

 lardi nom. sp. nov. In addition to these four species, E. agilis, E. cochlea, E. 

 cornuta (Schiitt), and E. pavillardi, previously occurring in the literature, we 

 have brought to light six new species from the plankton of the Pacific oi¥ 

 La Jolla, California, to wit: Erytliropsis extrudens sp. nor., E. richardi sp. nov., 

 E. hispida sp. nov., E. lahrion sp. nov., E. minor sp. nov.. and E. scarlatina 

 sp. nov. 



It has not been possible, in the brief tune and with the often scanty material 

 available for the inspection of the new species here described, to determine 

 all of tlie structural details essential for an adequate description. The loco- 

 motor activities and the ceaseless rapid contractions of the prod preclude con- 

 tinuous close observation while the normal structure persists, and c^'tolysis 

 abruptly terminates all possibility of further examination when activit}" ceases. 

 Discrepancies and inconsistencies with regard to such structures as the longi- 

 tudinal flagellum, the attachment area, and incomplete delineation of the com- 

 plicated contour and furrows of the epicone are attributable to these baffling 

 difficulties. 



The prod or tentacle itself is subject to great modification in shape, position, 

 and completeness during the period of observation. All of our figures have 

 of necessity been made from individuals which have slowed down. In these 

 the prod is foreshortened by contraction, and perhaps in some cases has even 

 undergone autotomy. It was not infrequently entirely lacking in some indi- 

 viduals under observation, as it is in Schiitt's (1895) figures of Ponchetia 

 cocJdea and P. cornuta. "While it is by no means certain that it is normally 

 present in both of these species of Schiitt, the fact that we have f oimd it present 

 in all species we have figured, including Erijthropsis cornuta (Schiitt), though 

 not in all individuals of these species which we have had under observation, 

 leads us to infer that it is a normal organ in the genus Erijthropsis, and will 

 ultimately be found in E. cochlea Schiitt also. In view of these considerations 

 we have included Schiitt's (1895) Pouchetia cochlea in Erijthropsis, although 

 no prod apjDears on his figures. 



It is obvious from an inspection of the comparative figures (see text fig. SS) 

 of the known species in the genus Erijthropsis that they fall into two groups, 

 those with diffuse or compound lenses and lolled or radiate pigment masses, 

 referable to the subgenus Pohjopsidclln and the suligenus Erijthropsis sensu 

 strictu, with condensed or simple undivided lens and compact pigment mass. 

 This first group exhibits the principle of repetition of parts and might be cited 

 as expressing multiple similar factors. Some degree of correlation between 

 lens and pigment spot appeai-s in the fact that subdivision of the lens is in 

 every case accompanied by radiations (E. hispida) or lobing (E. lahruw) of 

 the pigment mass, though not l)y its complete subdivision. On the other hand, 

 the remaining seven species of the genus have an undivided lens and a compact 

 pigment mass without trace of lobes. 



