MOLLUSCA OF THE ' CilALLEIfGER ' EXPEDITION. 27 



' Challenger/ P. craticici, Wats., seems the largest yet described- 

 Some of the others, though small, are remarkable for form or 

 sculpture, or both ; all, unfortunately, are represented by but a 

 few specimens. In addition to the Stations referred to below, 

 only three others afforded specimens of Functurella to the ' Chal- 

 lenger '; these are : — St. 312, in the Straits of Magellan ; St. 145, 

 between the Cape and Kerguelen ; and St. 119, at Kerguelen : 

 and at all these places the species obtained was our British 

 P. Noacliina, L. 



Looking at these facts, one is struck by the very large number 

 (no fewer than eight) of new species from one locality. Further, 

 if we take in connection with this the poverty of specimens from 

 that locality, and also the rarity of the genus in the dredgings in 

 general, we can hardly doubt that the true home of the genus 

 has not yet been found. 



Gren. Zeidoea, A. Ad. 



Zeidoea naueeaqa*, n. sp. 



St. 21. Mar. 25, 1873. Lat. 18° 38' 30" Is., long. G5° 5' 30" W. 

 Off St. Thomas, North of Culebra Island, Danish AV. Indies. 

 390 fms. Coral-mud. 



Shell. — White,, delicate, dei^ressed, oblong, pointed behind, 

 "with a minute short apex, rounded and cleft in front, with a broad 

 flat keel bearing the old cleft-scar and extending the whole 

 length of the shell: the enormous mouth is closed behind by a 

 crepidula-like partition. Sculpture. Longitudinals — from the 

 apex to the cleft across the middle of the back runs a broad 

 raised keel, flat on the top, where it is scored by the minute 

 delicate, sharp, prominent, close-set, but not contiguous scars of 

 the old cleft ; en either side it is bordered by a sharp marginal 

 line : from these marginal lines branch ofii' feeble irregular diver- 

 ging threadlets, betvv^een which, as they go wider apart, others 

 arise ; the intervals between them are two to three times the 

 breadth of the threadlets. Spirals — strictly speaking there are 

 none, but the whole surface is scored at right angles to the lon- 

 gitudinals with a series of threadlets, A^ery similar in form but 

 rather more closely set ; these radiate from the apex and indicate 

 the old mouth-edges. Colour porcellaneous white, which is dead ou 



* The name was suggested by the resemblance of the shell to a half-decked 

 boat which has been ship-ffrecked. 



