EXTRACTS FROM FOREIGN PERIODICALS. 99 



remarkable that all the examples of it are found collected within a radius of two 

 or three leagues only. 



5. Spirula Peronii. — It is a rare thing to find this common shell with its animal' 

 a fact which, according to MM. Robert and Leclenchet, is in some measure 

 explained by their having discovered that it is the prey and common food of the 

 Phgsalix, which swarm in the same equatoiial seas. The figures hitherto 

 published of the Spirula are incorrect ; it is a cephalopode which approaches re- 

 markably in form to the shell-less Loligo sepiola, having the shell almost entirely 

 imbedded in the posterior part of the body, where there are two natatory ex- 

 pansions of the cloak. The eye is proportionally very large, and without a lid. 

 — Annates des Sciences Naturelles ; as translated in the Mag. of Zool. and Bot., 

 Vol. i., p. 414. 



G. Parmacella, Cuvier. — MM. Webb and Vanbeneden have attentively exa- 

 mined the American mollusca, reputed to belong to this genus, in the rich 

 collection of the late Baron de Ferussac, and the result is, the establishment 

 of a new genus (Peltella) for their reception, the organic differences between 

 them and those of the old continent being so considerable as to justify their 

 separation. This division, besides, has the advantage of fixing in a precise 

 manner the geographical distribution of the two genera. The Parmacellce 

 belong more particularly to North Africa, one species only having been met 

 with at the western extremity of Europe, and in one of the warmest regions of 

 the Iberian Peninsula. We may then presume, that when the Limacidce of 

 North Africa are better known, the group to which the Pharmacellse belong, 

 will present a series of species similarly conformed, and replacing in those 

 climates the Slugs of our temperate regions. The European species is mi- 

 nutely described and figured in a late No. of Guerin's Magazin de Zoologie. 

 It was found on the hills of Alcantara, behind Lisbon, feeding on the young 

 shoots of Cochlearia acaulis, and is characterized as follows: — Parmacella Va- 

 lenciennii, corpore toto fulvo, reticulatim ruguso ; concha scutello obvoluta, 

 tenui, diaphana, fragilissima; spirae rudimento instructa, basi motaria amditu 

 sinuata. — Webb and Vanbenjeden in Mag. de Zoologie. 



BOTANY. 



7. Reproduction of Alg^:. — The eighth volume of the Societe de Physique et 

 cCHistoire Naturelle de Geneve, contains a paper read Dec. 17, 1835, by M. 

 Duby, on the propagation of the species of Ceramium. Highly important 

 conclusions have resulted from this memoir (the greater part of the materials 

 of which were furnished by M. Crouan, a naturalist of Brest), regarding the 

 physiology of the Alga, and especially of Ceramium. They may be reduced 

 to the following :— 



