NO. 9 MARINE INVERTEBRATES, ALASKA — MacGINITIE Jl 



lata, R; Porella compressa, i large; Cos facia surcularis, several; 

 Diplosolen ohelimn (C). Cirripedes — Clistosaccus pagnri, i; Pelto- 

 gaster depressiis, i; Balanus balanns (C) ; B. rostratus apertus (C). 

 Cumaceans — Diastylis dalli, few. Amphipods — Onisimtis affinis, 3 ; 

 Eusirus cuspidatiis, 4. Pelecypods — Pecten islandicus, 2; Musculus 

 discors, 30 (up to 9 mm.). Gastropods — Ptychatractus occidentalis, 

 2 ; Pyrulofitsus deformis, i small ; Beringius stimpsoni, 2 ; Colus 

 spitshergensis, 2 ; Neptunea sp., 3 ; Buccinimt plectrum, 5 ; Tricho- 

 tropis bicarinata, 2. Amphineurans — Symmctrogephyrus vestitiis, 5. 



Station 30-31 was on the oceanward side of Station 32 (see be- 

 low). The rubble bottom here was not quite so rich in animal life as 

 that on the shoreward side of Station 32. Some of the largest sea 

 urchins found were taken at this station but there were only a few 

 specimens. Animals : Sponges — Polymastia andrica, h (the only 

 specimen taken of this red, cylindrical sponge). Anthozoans (octo- 

 coral) — Eunephthya rubiformis, several col. Bryozoans — Hincksina 

 gothica, n. sp. (C) ; Emhallotheca stylifera (C); Porella miniita (C) ; 

 Cystisella fragilis, few; Lichenopora canalictdata, few; L. z>errucaria 

 (A). Ophiurans — Gorgonocephalus stimpsoni, 2. Echinoids — 

 Strongylocentrotus drobachiensis, several. Amphipods — Photis rein- 

 hardi, 5. Gastropods — Beringius stimpsoni, 2; Neptunea ventricosa, 

 2; Buccimim plectrum, 10; Margarites costalis, 6. Amphineurans — 

 Trachydermon albus, 5. 



Station 32 was a complete surprise. It was a canyon 12. i miles 

 from shore, of undetermined length, about 0.25 mile wide and 741 

 feet deep, with fairly abrupt walls. The floor of the ocean was at a 

 depth of 438 feet on the shoreward side of the canyon and 522 feet 

 on the oceanward side. The substratum of the canyon was mud, but 

 it was soft, and not stiff, sticky, or clayey like that of the mud zone 

 near shore. As far as could be determined, the entire floor of the 

 canyon was covered with worm tubes of the terebellid Pista maculata. 

 Dredge hauls brought up bushels of them. Dr. Pettibone identified 

 27 other species of polychaetes that occurred in lesser numbers among 

 the tubes of Pista. Of these 27 species 1 1 were tube dwellers also : 

 Flabelligera affinis, i ; Nicomache lumbricalis, i ; Pectinaria granu- 

 lata, 5 ; P. hyperborea, 10; Nicolea venustida, i ; Terebellides stroemi, 

 i; Thelepus cincinnatus, i; Euchone analis, i ; Potamilla neglecta, 9; 

 Sabella crassicornis, 3; and Spirorbis granulatus, i. There were 5 

 species of polynoids : Arcteobia antic ostiensis, 1 ; Enipo gracilis, 1 ; 

 Gattyana cirrosa, 11 ; Harmotho'e extenuata, 43; and H. imbricata, i. 

 Arcteobia antic ostiensis is known to be commensal with Pista flexuosa 

 (Labrador) and Enipo gracilis with Nichomache lumbricalis (Alaska ; 



