IMMATURE SPECIMENS OF PENELLA FILOSA. 307 



must run a course similar to that in Lerncsa, and if only a newly- 

 attached mating-stage larva could be identified and described, it 

 would go far toward the unravelling of the life-history of these 

 highly-modified copepods. 



Similarly, the discovery of the males for this genus is much to 

 be desired. Steenstrup and Liitken ('60 record finding near 

 the egg-sacs of a Penella exocceti two almost microscopic animals 

 which reminded them of the " pigmy males of other lernaean 

 forms." They figure one of these with the suggestion that it 

 may be the vainly sought male. The specimens could not be 

 removed for study. It is very doubtful whether this is a male 

 of Penella. It would seem that the male of this genus ought 

 rather to resemble the male of Lcrncza and its form will be cyclo- 

 poid much like that of the chalimus stage of the females. As 

 with Lcrncea also, it is unlikely that the males remain attached to 

 the females after fertilization has taken place, but continue on 

 the host which has served them for their earlier development, 

 while the females become free swimming after fertilization and 

 settle down on another animal of the same or another species 

 from the first host. 



CLARK UNIVERSITY. 



LITERATURE CITED. 

 Brady, G. S. 



'83. Report on the Copepoda of the Challenger expedition. Challenger Reports, 



Zool., 8, p. 136, pi. LV., fig. 9-13. 

 Claus, C. 



'68. Beobachtungen uber Lernseocera, Peniculus und Lernaea. Marburg, 1868, 



pp. 16-27, pl- III. -IV. 

 Lubbock, J. 



'60. On some oceanic Entomostraca collected by Capt. Toynbee. Trans. Linnean 



Soc. Lond., XXIII., p. 196, pl. XXIX., fig. 40. 

 Liitken, Chr. 



'93. Slaegten Baculus Lubbock et udviklingstrin af Penella. Vidensk. Meddel- 



elser, ser. 5, XV., pp, 73-76. 

 Steenstrup, J. J. S., Lutken, C. F. 



'61. Bidrag til Kundskab om det aabne havs snyltekrebs og Lernaen. K. D. 



Vidensk. Selsk. Skrifter, ser. 5, V., pp. 408-419, pl. XIV. 

 Scott, A . 



'01. Lepeophtheirus and Lernsea. Liverpool Mar. Biol. Memoirs, pp. 43-45, 



pl. IV. 

 Wierzejski, A. 



'77. Ueber Schmarotzerkrebse von Cephalopoden. Zeit. fur Wissensch. Zool., 

 XXIX., pp. 572-574, pl. XXXII. -XXXIII. 



