FISHERY BULLETIN: VOL. 71, NO. 1 



Table 9. — Species and density, by station, of gastropods 

 that occurred at only one station each. 



Table 10. — Density distribution of gastropod shells, all 

 species combined, in relation to water depth. 



Species 



Station 



Specimens 



Alvania janmayeni 

 Calliostoma occidentalis 

 Calliostoma sp. 

 Cavolina longirostris 

 Cavolina tridentata 

 Epitonium groenlandicum 

 Epitonium multistriatum 

 Eidimella smithi 

 Eulimella sp. 

 Eupleura caudata 

 Fossarus elegans 

 Lunatia heros 

 Mitrella lunata 

 Neptunea decemcostata 

 Odostomia gibboia 

 Pieudorotetla solida 

 Pyramidella sp. 

 Retuia obtusa 

 Solariella iris 

 Taranis cirrata 

 Turrtellopsis acicula 



55 



23 



53 



51 



53 



52 



23 



37 



6 



29 



52 



1 



27 



31 



1 



38 



21 



5 



9 



9 



37 



Nolnfi 

 20 

 20 

 10 

 10 

 20 

 10 

 30 

 10 

 20 

 10 

 10 

 10 

 10 

 10 

 40 

 40 

 10 

 40 

 30 

 10 

 10 



7,1' , 



20 



.BLOCK 



ISLAND 



J I I Il2! — L.^ \ 1 pf. 



.' MARTHA'S VINEYARD 



NANTUCKET 





ipOO METERS 



CrZ3 0-50 



GASTROPODA 

 NUMBER PER m' 

 [°1 60-250 ^3250- IPOO 



T 1 1 — yTji 1 r 



41' 



■40» 



T — ^TQi — I 1 1 r 



Figure 12. — Density distribution of gastropod shells, all 

 species combined. 



Table 8. Species with a wide geographic dis- 

 tribution were, in decreasing order: Alvania 

 carinata, Mitrella zonalis, Cylichna gouldi, Colus 

 pygmaeus, Odostomia canaliculata, Epitonium, 



Miters 



20-29 



30-39 



40-49 



50-59 



60-69 



70-79 



80-89 



90-99 



100.124 



125-149 



150-174 



175-199 



200-249 



250-567 



Number 

 1 



6 

 7 

 8 

 5 

 9 

 I 



7 

 4 

 4 

 1 



5 

 •2 

 1 



Percent 



100 



83 



71 



63 



100 



89 







100 



100 



75 



100 



100 



100 



100 



No/m^ 



10 



35 



84 



96 



190 



221 







51 



72 



80 



60 

 102 

 140 



65 



dallianum, Cylichna alba, Nassarius trivittatus, 

 and Turbonilla interrupta. 



Four patterns of geographical distribution 

 are revealed: (1) The most common is a rela- 

 tively narrow east-west band across the area in 

 either shallow or deep water, typified by Balcis 

 intermedia, Crepidula fornicata, Drillia lissotro- 

 pis, Epitonium dallianum, and others. (2) Com- 

 paratively broad east-west bands across the area 

 are illustrated by Mitrella zonalis and Turbonilla 

 interrupta. (3) Peripherial occurrence around 

 the fine-grained bottom sediments located in the 

 center of the area is illustrated by Cylichna alba, 

 Odostomia canaliculata, and to some extent by 

 Rissoa sp. (4) Distribution in the central part 

 of the area, a pattern nearly opposite that of 

 peripheral distribution (pattern number 3), is 

 illustrated by Alvania carinata. 



Bathymetric range differed markedly among 

 species. The minimum, maximum, and mean 

 depth of occurrence for each species is listed in 

 Table 11 and illustrated for the more common 

 species in Figure 14. Mitrella zonalis was the 

 only species taken over a wide range of water 

 depths (62 to 567 m). Species that had a mod- 

 erately wide depth range were: Buccinum 

 undatum, Cylichna alba, Epitonium novangliae, 

 Odostomia canaliculata, and Rissoa sp. 



Species found in shallow water — those re- 

 stricted to depths of 50 m or less — were: Crepi- 

 dula fornicata, Eupleura caudata, Lunatia her- 



20 



