396 Miscellaneous. 



of the shell like the Nautili and Ammonites. Persuaded that a care- 

 ful investigation of the structure of the Nummulites could alone 

 decide respecting the form of the animal which constructed these 

 singular habitations, we set earnestly about it, and after frequently 

 repeated observations and sections, fractions, sawings and grindings, 

 and having examined with the microscope a multitude of Nummulites 

 as hard as quartz or the most compact limestone, we had the good 

 fortune to meet with a number from which we might remove suc- 

 cessively the circumvolutions of the spire by means of a kind of 

 cleavage, which has led us to conclude : — 



1. That the Nummulites were external multispiral shells with 

 enveloping convolutions, and at the same time polythalamian. 



2. The sides of these shells were perforated in a similar manner 

 to what is observed in the Rotalia and Nonionina. 



3. It was through these holes that the numerous tentacula or 

 pseudopoda with which the animal was provided were exserted 

 (organs of prehension or locomotion). 



4. The septa of the chambers leave a triangular aperture between 

 them and the last-formed convolution of the spire by means of which 

 they all communicate. 



5. All the chambers were occupied at the same time by the multi- 

 segmented body of the animal. 



6. The several segments were connected with one another by a 

 tube or sipho, which at the same time fulfils the office of digestive 

 canal. 



7. The animal increased by producing new segments which were 

 added in the same plane to those previously existing. These seg- 

 ments were soon enveloped by the calcareous matter which they 

 secreted, like the mantle of the MoUusca. 



8. The inhabitant of the Nummulites was neither a Polyp nor a 

 Medusa, nor an Annelide nor a Cephalopodous moUusk, but one of 

 those long misunderstood creatures for which D'Orbigny created the 

 name of Foraminifera. — Comptes Rendus, Oct. 25, 1847. 



Description of the Caligus Stromii. By W. Baird, M.D., F.L.S. &c. 

 In 1 845 I found upon a salmon at Berwick a species of Caligus 

 which, at that time, I thought Avas new. Upon more careful ex- 

 amination I found it approached very near the Caligus Vespa of M. 

 Edwards, differing however considerably in size and other more 

 minute distinctions. In the Copenhagen Transactions, vol. x. p. 23, 

 and t. 7. f. 1-6, the celebrated Strom has described and figured a 

 species of Caligus under the name of " Laxe luus " or salmon louse, 

 and which he shortly defines " Monoculus thorace abdomineque 

 ovato, Cauda lobata." It is evidently the same as the specimens I 

 found upon the salmon of the Tweed, and as Strom is the only author 

 who seems to have noticed it, I have named it after him. 



without any apparent aperture and iuteinally a spiral cavity divided by septa 

 into a number of minute chambers, but without a sipho (Regne Animal, 

 iii. p. 22) ; which is the same thing as saying, that these chambers had no 

 communication with each other nor with the exterior. From our examination 

 of these fossils we have been led to admit the very opposite. 



