28 Mr. J. Blackwall on the Structure, Functions, (Economy, 



Placentadce. Animal free. Foot cylindrical, compressed, me- 

 dial, without any byssal pore. Vent attached to the right leaf of 

 the mantle. Pedal muscle small, leaving a small round scar be- 

 tween the diverging cardinal plates. 



This family must be removed to the tribe of Anomiaina, 

 having a distinct foot. The mantle leaves free, margin closely 

 bearded. Foot when contracted in spirits compressed, elongate, 

 larger at the end, truncated, and with a deep linear cavity at 

 the end, apparently produced by the withdrawing of the tip, 

 probably cylindrical, and much elongated and produced when 

 alive. Gills suspended, occupying the front and lower edge. 

 Anus tubular, conical, elongate at the hinder basal margin, at- 

 tached to the inner side of the right mantle leaf. Lips elongate, 

 attached by their hinder edge. Body surrounding the cardinal 

 ribs and cartilages. 



Pectenidae. — The foot of Pedum is elongate, cylindrical, clavate, 

 rather enlarged and rounded at the tip, without any appearance 

 of a byssal groove. 



III. — Supplement to a Catalogue of British Spiders, including 

 remarks on their Structure, Functions, (Economy and Systematic 

 Arrangement. By John Blackwall, F.L.S. 



[Continued from vol. xi. p. 120.] 



Tribe OCTONOCULINA. 



Family Salticid.e. 



Genus Salticus, Latr. 



After Salticus notatus in the supplement to the catalogue 

 (Annals and Mag. of Nat. Hist. Second Series, vol. xi. p. 114) 

 add 



Salticus promptus. 



Salticus promptus, Blackw. Annals and Mag. of Nat. Hist. Second 

 Series, vol. xiii. p. 1/3. 



In October 1853, an immature female of this species, wbich 

 is nearly allied to Salticus frontalis and Salticus reticulatus, was 

 received from the Rev. Hamlet Clark, who took it near North- 

 ampton in the autumn of the same year. 



After Salticus reticulatus in the supplement to the catalogue 

 (Annals and Mag. of Nat. Hist. Second Series, vol. xi. p. 114) 

 add 



