ZOOLOGY. 697 



odontophore, with three rows of rhachidian teeth, and on each side a 

 broad bilobed inner lateral, and two rows of small, hook-shaped outer 

 lateral teeth (1.1 + 1.2 x 2) ; with frontal tentacles, united by a fold and 

 small posterior tentacles, and with a heliciform shell provided with a 

 paucispiral operculum. 



Although the living shells have been referred to the same species as 

 the fossilized, they have been distinguished as a variety (named tenera), 

 inasmuch as they have a "much thinner and more fragile texture," but 

 this difference, it is suggested, "maybe due to mere local conditions." 



It should be added that the gills of the Choristiids are "large, attached 

 to the inner surface of the mantle on the left side of the neck, and ex- 

 tending over to the right side, consisting of numerous lamellae. {Proc. 

 TJ. 8. Nat 31us.,y. 5, p. 337.) 



A new deep-sea family of Docoglossates. 



The family Cocculinidae has been proposed for two limpet-like mol- 

 lusks, of deep water, exhibiting a peculiar combination of characters. 

 The two are congeneric, representing a new genus called CoccuUna, and 

 belong to the order of Rhipidoglossa. The dentition is typical — 

 50-150 (1 + 3) I (3 + 1) 150-50— and resembles that of the Fissurellidae 

 aud Helicinidae; but there is only a single asymmetrical gill, no append- 

 ages to the side of the foot or on the mantle are developed, and the shell 

 is patelliform, unfissured, unsinuated, and entirely external. The spe- 

 cies have been found at the depth of over 100 fathoms east of the New 

 England coast, and in deeper water in the Caribbean Sea. 



A new deep-sea family of Fissurelloid Bhipidoglossates. 



The family Addisoniidae has been constituted for the reception of a 

 remarkable limpet-like Gastropod found about 75 miles south and west 

 from Martha's Vineyard, at a depth of from 96 to 130 fathoms. The 

 mollusk belongs to the order of Rhipidoglossa, but has a very peculiar 

 dentition, viz, 1 (1 + 2 + 2) I (2 + 2 -f 1) 1 — the single uncini being flat 

 and scale-like. The parts are very asymmetrical, and there is an enor- 

 mously developed lateral series of separately inserted gill-laminae, like 

 those of the Patellidae, but no filamentary appendage of any kind. The 

 shell is asymmetrical and porcellanous. The type is interesting as being 

 a generalized — or what would have been called by Agassiz a " syn- 

 thetic" — form. The species has been named Addisonia paradoxa. 



The Pseudomarginellw. 



In the annual report of the Smithsonian Institution ior the year 1880, 

 a notice of a j)reliminary article by Dr. Justus Carriere on Marginella 

 glabella and Pseudomarginella was given. Dr. Carriere claimed to have 

 found in shells having the aspect of ^^ Marginella glabella'''' animals 

 exhibiting three very different types of dentition. It was then supposed 

 by the reporter that the statement that the shells associated with the 



