NO. 9 MARINE INVERTEBRATES, ALASKA — MacGINITIE I5I 



Balanus balanus (Linnaeus) was the least abundant. Specimens 

 were taken at Eluitkak Pass and at 328 and 438 feet. 



Next in abundance was B. rostratus apertus Pilsbry, which grows 

 embedded in masses of sponge (see "Porifera"), with only the aper- 

 ture open to the outside. A group of a dozen or more individuals 

 growing one upon another may be surrounded by sponge. This bar- 

 nacle was taken with Topsentia disparilis at 438 and 341 feet, and 

 with Myxilla incrnstans at 125, 328, and 217 feet. 



Balanus crenatus Bruguiere is one of the most abundant sessile ani- 

 mals in the waters off Point Barrow. It occurred in profusion at 

 Eluitkak Pass and in all hauls from stony bottom from 1 10 to 522 feet. 

 It was even found on mud bottom attached to snail shells and old clam 

 shells. On August 3, 1948, a specimen attached to a snail shell had 

 numerous tiny barnacles growing on it, and on August 30 a haul from 

 Eluitkak Pass revealed new sets of young barnacles on everything 

 to which they could attach — stones, shells, and even the isopods 

 Idotaega entomon and /. sahini. Young from i to 1.5 mm. in diame- 

 ter were abundant at 184 feet, and a young set was found attached to 

 adult B. crenatus at 216 feet. 



Order RHIZOCEPHALA 



Two species of rhizocephalan parasites, identified by Dr. Edward 

 G. Reinhard, were found. In both species the host is the pagurid 

 Pagurus trigonocheirus. 



One mature Clistosaccus pagiiri Lilljeborg was taken on a male 

 pagurid at 438 feet; one very young specimen from a female pagurid 

 at 217 feet, and another at 72 feet. The pagurid represents a new 

 host and the copepods from Point Barrow extend the range north- 

 ward from the 58th to the 71st parallel of latitude. 



A single Peltogaster depressus Reinhard was taken from a male 

 pagurid at 438 feet. Only two other specimens of this cirriped, both 

 from Pagurus capillatus (Benedict), have been reported: one from 

 off Kodiak Island, and one in the Bering Sea, taken by the Albatross 

 in 1893 and 1897 (see Reinhard, 1944). Pagurus trigonocheirus 

 therefore represents a new host, and the extension of range of the 

 cirriped is the same as that of the above species. 



Order MYSIDACEA 



Only three species of mysids were collected. The writer is indebted 

 to Dr. Albert H. Banner for identifying them. 



Two ovigerous females of My sis oculata (Fabricius) were taken 



