The inconspicuous yoldia is represented by three speci- 

 mens from one sample in our collection (Table 5). 



Our sample is from the continental shelf south of Nantucket 

 Shoals (Fig. 92; Theroux and Wigley footnote 4, table 162). 



This species occupies water depths which range between 

 183 to 1,290 m (Abbott 1974). 



Our sample is from a water depth of 59 m. This depth places 

 it in the 50-99 m depth range grouping. 



The sample in the NEFC collection was obtained in a sand 

 sediment. 



Portlandia inflata (Verrill and Bush 1897). Inflated yoldia. Fig- 

 ure 93. 



This species normally occurs from off Massachusetts to 

 North Carolina (Johnson 1934; Clarke 1962; Abbott 1974). 



The inflated yoldia is represented in the NEFC collection 

 by 197 specimens obtained from 24 samples (Table 5). 



The majority of samples in the NEFC collection are from 

 north and east of Cape Cod in the Gulf of Maine; however, 

 there are two samples on the outer continental shelf and upper 

 slope south of Nantucket Shoals (Fig. 93; Theroux and Wig- 

 ley footnote 4, table 163). 



The depth range for this species is between 73 and 2,943 m 

 (Abbott 1974). 



Our samples are from depths which range between 55 and 458 

 m with a mean of 259 m. The largest amounts of both samples 

 and specimens are in the 200-499 m depth range grouping 

 which contains 75% of the samples and 92% of the specimens; 

 the 50-99 m grouping contains 21% of the samples and 6% of 

 the specimens, and the 100-199 m grouping contains 4% of the 

 former and 2% of the latter (Table 48). 



The greatest number of samples (50%) occurred in clay 

 substrates; however, the largest number of specimens oc- 

 curred in sand-gravel which contained 65% of the specimens 

 but only 17% of the samples; clay sediments contained 20% of 

 the specimens; other sediment types in which this organism 

 was found were till, with 4% of the samples, and 0.5% of the 

 specimens, and silt which contained 25% of the samples and 

 13% of the specimens (Table 49). 



Portlandia iris (Verrill and Bush 1897). Iris yoldia. Figure 94. 



This species occurs from the Gulf of St. Lawrence to North 

 Carolina as well as being distributed in some sections of the 

 Arctic (Johnson 1934; La Rocque 1953; Ockelmann 1958; 

 Morris 1973; Abbott 1974). 



The NEFC Specimen Reference Collection contains 334 

 specimens of the iris yoldia from 47 samples (Table 5). 



The NEFC samples are principally from the Gulf of Maine 

 region, but four samples occur on the upper continental slope 

 off Long Island, N.Y. (Fig. 94; Theroux and Wigley footnote 

 4, table 164). 



Gosner (1971) placed this species in the Boreal and Virgi- 

 nian zoogeographic provinces. 



Published reports on the depth distribution of this species 

 list it as occurring between 37 and 2.928 m (Gosner 1971: 

 Abbott 1974). 



The range in depth of our samples is between 15 and 376 m 

 with a mean of 191 m. There is a gradual diminution in the 

 abundance of both samples and specimens with decreasing 

 water depth with regard to depth range groupings. The major- 



ity of samples (55%) and specimens (61%) are in the 200-499 m 

 depth range grouping, while the 100-199 m grouping contains 

 28% of the samples and 26% of the specimens; the 50-99 m 

 grouping contains 15% of the samples and 13% of the speci- 

 mens, while the shallowest depth range grouping, 0-24 m, 

 contains only 2% of the samples and 0.3% of the specimens 

 (Table 50). 



Our data show that this species prefers finer grained sedi- 

 ments to the coarser ones with the majority of both samples 

 and specimens occurring in the three finest grained sedi- 

 ments, clay, silt, and silty sand: clay contained 30% of the 

 samples and 38%' of the specimens, silt sediments contained 

 15% of the samples and 13% of the specimens, while silty sand 

 substrates contained 28% of the samples and 35% of the 

 specimens. Sand substrates contained 7% of the samples and 

 7% of the specimens, till 15% of the samples and 5% of the 

 specimens, gravel, the coarsest, contained only 4% for sam- 

 ples and 2% for specimens (Table 51). One sample containing 

 three specimens is unclassified with regard to sediment type. 



Portlandia lenticula (Moller 1842). Figure 94. 



The widest distribution of this species occurs in Arctic 

 regions according to Ockelmann (1958) where he considered 

 it to be panarctic and possibly circumpolar. In Boreal areas it 

 occurs north of Cape Cod. Mass. (Johnson 1934; Abbott 

 1974). 



This is a rather uncommon species of which there are four 

 specimens from four samples in our collection (Table 5). 



Our samples are from the Gulf of Maine and Massachusetts 

 Bay (Fig. 94: Theroux and Wigley, footnote 4, table 165). 



Johnson (1934) and Abbott (1974) reported the depth range 

 for this species in southerly regions to be from 201 to 223 m, 

 while Ockelman (1958), giving the depth distribution for 

 northern regions, listed it as occurring from to 1,400 m. 



Our samples are from water depths which range between 59 

 and 265 m with a mean of 122 m. The 50-99 m depth range 

 grouping contains 75% each of samples and specimens, while 

 the 200-499 m grouping contains 25% of each (Table 52). 



The distribution of samples and specimens with regard to 

 sediment type is similar to that which occurred for depth 

 range in that 75% of both samples and specimens occurred in 

 one sediment type, silty sand, while 25% of each occurred in 

 silt (Table 53). 



Portlandia lucida (Loven 1846). Lucid yoldia. Figure 95. 



The lucid yoldia is distributed from Greenland to North 

 Carolina in the Northwest Atlantic and from Norway to the 

 Mediterranean in European waters, as well as being wide- 

 spread throughout Arctic regions (Johnson 1934; La Rocque 

 1953; Ockelmann 1958; Clarke 1962; Tebble 1966; Morris 

 1973: Abbott 1974). 



Portlandia lucida is uncommon to rare; it is represented in 

 the NEFC collection by 161 specimens from 27 samples 

 (Table 5). 



Our samples are distributed in the Gulf of Maine to the 

 north and east of Cape Cod, Mass. (Fig. 95; Theroux and 

 Wigley footnote 4. table 166). 



The main distribution of this species according to Ockel- 

 mann (1958) is low Arctic-boreal, and Mediterranean- 

 Atlantic, and is abyssal in the North Atlantic only; Gosner 

 (1971) placed it in the Boreal and Virginian provinces. 



10 



