A REVIEW OP THE VOLUTIDAE 



conical or trochoid, polished, unaculptured 

 and consisting of few whorls. Prom the 

 trochoid evolved the puplform and the bulb- 

 ous nucleus, the latter a variation of the 

 trochlform In the planorbold coll. The 

 enormous Cyiblum nucleus Is of trochoid 

 type but greatly exaggerated and dome-like, 

 being as large as the end of a pigeon egg. 

 This Is characteristic of the genus Cymbium 

 as contrasted with Cymba. 



A type of nucleus which begins with 

 a horny protoconch is described by Dall 

 from material obtained on a voyage of the 

 Albatross while off Patagonia. The materi- 

 al which formed the basis of this study 

 consisted of ovlcapsules of Adelomelon 

 maiellanlca. These were circular, about 

 an Inch In diameter, with a flat base at- 

 tached to a valve of Pec ten. The upper 

 part of each capsule consisted of a rounded 

 dome, exactly like the ovlcapsule of Volu- 

 topsis from Alaska, and like that contain- 

 ing two to four surviving larval shells. 

 The apical point was found to be acutely 

 conical, slightly twisted, and in the 

 youngest specimen still retained some 

 shreds of the extremely fragile membranous 

 protoconch adhering to the first whorl. 



A deplorable fact is the habit of 

 dealers who grind and polish every Volute 

 they can put their hands on, with the re- 

 sult that it is impossible to tell with ac- 

 curacy what sort of nucleus the recent 

 Volutes possess. Fossil shells are often 

 much more satisfactory for purposes of 

 study as no one considers that they are 

 worth polishing, and therefore are left in 

 the natural state. Many of the specimens 

 in museums, even the National Collection, 

 have been partially ruined, and students 

 are warned when examining specimens to make 

 due allowance for this damage. Otherwise 

 conclusions drawn may be at variance with 

 the truth. 



There is a great extension of the 

 mantle in certain groups of the Volutidae. 

 Thus there is deposited in some cases a 

 coat of enamel over the entire shell as in 

 Cypraea. A good example of this disposi- 

 tion of enamel is Zidona aniulata. 



DISTRIBUTION 



In common with other abyssal mol- 

 luscs the deep-water Volutes are already 



known to be rather widely dispersed. Among 

 the deep sea forms are many isolated types 

 which have been shifted about from one fam- 

 ily to another. Those now retained in the 

 Volutidae are generally known to be genuine 

 members of this family, due to extensive 

 anatomic studies of the soft parts. This 

 applies to the genera Xeptuntopsis and 

 Voluticorbts which so far have only been 

 taken living off the Cape of Good Hope in 

 moderate depths. The genus Volutomltra of 

 Gray includes a small compact group, the 

 two species being confined to Boreal Se^-S, 

 one in the North Atlantic adjacent to Green- 

 land and Iceland, the other species in or 

 near Bering Sea in an average depth of 75 

 fathoms and extending southward in the Pa- 

 cific to a point off San Diego, California, ' 

 where it occurs at a depth of 822 fathoms. 

 The range of the genus Valuta s.s. 

 requires further study. In a general way 

 the group is known to extend from the north 

 coast of South America through the Caribbean 

 and Gulf of Mexico, Valuta musica has been 

 reported from th3 east coast of Florida but 

 the specimen may be adventitious, and fur- 

 ther records are required before it may 

 safely be included In the fauna of that 

 state. Valuta musica has, together with 

 its various subspecies, been reported from 

 the West coast of Africa as well as the 

 Antilles. Valuta utrescens has been col- 

 lected upon the shores of Texas while the 

 large slender form of this species appears 

 to be confined to the west coast of Africa. 

 V. virescens varies greatly in size and 

 this no doubt is largely due to peculiar 

 environmental conditions rather than lati- 

 tude. Shells of the musica type are said 

 to be inhabitants of shallow water and may 

 be sought for after dark among rocks e-x- 

 posed at extreme low tide. 



Essentially an Atlantic genus 

 Aurinia appears to be confined to American 

 waters, chiefly in the region of the Carib- 

 bean, The species occur at moderate depths 

 and Include the well-known y4ur in ia junonia • 

 Allied to this group is the genus Bathy - 

 aurinia established by Clench and Aguayo 

 in 1940 to include the species torrei and 

 piratica. Bathyaurlnia has been obtained 

 off Cuba in from 10 to around 265 fathoms. 

 The genus, so far, has not been reported 

 elsewhere but it is likely to occur gen- 

 erally in Antillean waters. 



In the Cape Horn region and southern 



