NO. 9 MARINE INVERTEBRATES, ALASKA — MacGINITIE I23 



Phylum CTENOPHORA 



Like the jellyfishes, the comb jelHes were much more abundant 

 alongshore during the drift-ice summer of 1948 than during the open- 

 water summers of 1949 and 1950. Three species, each belonging to a 

 different order, were identified. At times all three would be abundant 

 at the edge of the water and again only one or two species would be 

 in evidence from the shore; at other times none were seen. Some- 

 times they would be washed ashore in great numbers. 



Mertensia ovum (Fabricius) was especially abundant on July 26, 

 1948, and again on September 30, 1949. On both of these dates the 

 majority of the specimens were about 10 mm. long, but individuals 

 up to 60 mm. in length were observed at various times. Some indi- 

 viduals taken on the morning of August 5, 1948, were gorged with 

 plankton; one 9 mm. long and 7 mm. in diameter had ingested one 

 appendicularian, several copepods and ostracods, strings of diatoms, 

 protozoans, arrow worms, nauplii, and a piece of red tentacle. 



In the summer of 1948 Bolinopsis injundihuliim (O. F. Miiller) 

 was first observed on August 2, when a specimen only 55 mm. long 

 and 35 mm. wide was taken alongshore. Later, individuals exceeding 

 200 mm. in length were common. 



Although it never occurred in such enormous numbers as either 

 Mertensia or Bolinopsis, the rose-colored Bero'e cucumis Fabricius 

 was more frequently present along the shore than were the other two 

 species. In 1948 it was first observed on July 20, in 1949 on July 22, 

 and in 1950 on July 20. In 1949 it was observed alongshore until 

 September 30, and throughout the winter fragments were seen in 

 leads or were taken through holes in the ice. 



Bero'e cucumis could be preserved satisfactorily, but despite time 

 and effort spent on the other two species, no success was achieved. 

 Solutions that preserved the animals also contracted them to such an 

 extent that they could not be worked on, and those that left the ani- 

 mals in a relaxed, transparent state completely dissolved them within 

 a period of six months. 



Point Barrow would be an excellent place for life-history studies 

 of the ctenophores, for often all stages of development from larvae to 

 adults are present at one time. 



Phylum PLATYHELMINTHES 

 Class TURBELLARIA 



Only two species of polyclad flatworms were taken, but one of 

 these, Noto plana atomata (Muller), was present in every dredge haul 

 from a bottom that afforded niches and hiding places, namely, Eluitkak 



