THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY, 



No. 76. SEPTEMBER 1843. 



XIX. — Upon the Anatomy 0/ Phalangium Opilio (Lafr.). 

 By Alfred Tulk, Esq., M.R.C.S., M.E.S. 



[With a Plate.] 



With the exception of the treatise by Treviranus upon the sma- 

 tomy of Phalanpum, Die Afterspinne,m his ^VermischteSchriften/ 

 I am not aware that any author has since given a detailed ac- 

 count of the structural peculiarities of this very singular family 

 of Arachnidans. The observations of Latreille*, Ramdohrf, Her- 

 mann J, Marcel de Serres§, Herbst|| and others, are limited to 

 particular organs, most of which are described and figured in too 

 superficial a manner ; while those made by Treviranus, though ex- 

 cellent as a whole, are yet wanting in sufficient minuteness, and 

 several interesting parts have been either entirely overlooked, or 

 but cursorily alluded to. I have endeavoured, therefore, in the 

 present paper to supply, as far as the delicacy of the objects dis- 

 sected would permit, the above deficiencies, and, in communica- 

 ting the results of investigations commenced during the summer 

 of 1843, to enter into a more full and accurate description of the 

 anatomy of the Harvest Spider than has hitherto appeared. The 

 species which I have selected for this purpose is Phalangium 

 Opilio, as it is the most abundant about London, and has been 

 regarded also as tjrpical of the genus to which it belongs. 



External Anatomy. — The dermo-skeleton of Phalangium is 

 constituted, as in the other Arachnida, by the external integu- 

 ment, which is continuous over the whole body, but variously 

 disposed and inflected, to form prolongations for the lodgement 

 of the different viscera and attachment of muscles. Its texture is 

 tough and coriaceous, as in the true spiders, and of a firmer con- 

 sistence at the anterior than the posterior extremity of the ani- 

 mal, namely, upon the upper and under surface of the cephalo- 



* Hist. Nat. des Fourmis : Paris, 1802. 



f Ueber die Verdauungsvverkzeuge der Insekten, 1811. 



X Mem. Apterologique, 1804. § Mem. du Mus. 



II Natur. System der Ungeflugelten Insekten: Berlin, 1797. 



Ann, ^ Mag, N, Hist, Vol, xii. M 



