MUSEUM OF COMPARATIVE ZOOLOGY. 117 



This little shell has a wide distribution ; the farther north it is found, the 

 larger it gi'ows. Some Arctic specimens measure 12.5 mm. in height ; these, 

 about one tenth as much, or ygVo "^ *^^ ^^'•^^ "^ ^^^ former. There is no doubt 

 as to its identity with U'Orbigny's Nuculocardia. 



Modiolaria sp. indet. 

 Yucatan Strait, 640 fms., one dead valve. 



Mytilus exustus Linnb. 



Mytilus exustus Linne, D'Oibigny, + J/. Lavalleanus D'Orbigny + il/. Domingucnsis 

 D'Orbigny, loc. ciL, Tab. XXVIII. 



Sigsbee, off Havana, 158 fms. ; Barbados, 100 fms., etc.; thence to shallow- 

 water. 



Avicula sp. indet. 

 Station 26, 116 fms., dead, perhaps washed from shoaler water. 



AmussiurQ lucidum Jeffreys. 

 Plcuronedia lucida JeftVeys, Depths of the Sea, p. 464, fig. 78. 



Station 2, 805 fms.; Station 21, 287 fms.; Yucatan Strait, 640 fms.; Station 

 5, 229 fms.; Station 35, 804 fms.; Station 3, 243 fms.; Station 19, 310 fms.; 

 Station 47, 331 fms.; Sigsbee, off Havana, in 119, 127, 243, 450, and 480 fms.; 

 off Morro Light, 292 fms.; Station 7, off Cape San Antonio, 424 fms. ; Station 44, 

 539 fms. ; Gulf of Mexico, west of Florida, 30 fms. ; Charlotte Harbor, Florida^ 

 13 fms. 



This is one of the most common and pretty of the abyssal species in the 

 Antillean and Gulf region. Variety marmoratum, from all depths, is beau- 

 tifully mottled with scarlet, opaque white, and orange ; many specimens are 

 dotted all over with opaque white dots. I have reason for suspecting that 

 this, or a nearly allied species, attains a much greater size, perhaps two or 

 three inches in length. It will be observed that the ordinary form ranges 

 from a few fathoms on the coast of Florida to the greatest depths of the region; 

 and there is no difference whatever between the specimens from shallow and 

 those from deep water. The same may be said of Gouldia cubaniana. 



Pecten sp. indet. 



A fresh valve of a small, aculeately sculptured, scarlet Pecten was obtained 

 from 804 fms. 



Spondylus sp. indet. 



Young specimens and one adult valve of a pink striated Spondylus were ob- 

 tained from 640 fms. in the Yucatan Strait. 



