822 Dr. G. C. Wallich on the true 



them) the upper fore extremity of their falces is furnished 

 with strong spines. In the present spider, whose nest is made 

 in channels already existing, the crevices and rugulosities of 

 the bark of trees, there is no need of such spines ; and their 

 absence is thus accounted for. An interesting speculation 

 suggests itself here, i. e. whether the present spider is prior 

 or subsequent in point of genealogical relationship to the trap- 

 door spiders that form a nest in the earth, and are specially 

 furnished with spines on the falces to excavate the holes for 

 it. It is, it seems to me, most conceivable that spiders should 

 first take advantage of sites already suited for their habita- 

 tions, and that subsequently the species fitted for forming their 

 own sites should be gradually developed. 



EXPLANATION OF PLATE X. 



Fig. 1. a, spider, enlarged ; b, ditto, in profile, without legs or palpi ; 



c, eyes, from above and behind ; d, underside of cephalothorax, 



showing maxillae, labium, sternum, and basal joints of the legs; 



e, tarsus of one of the second pair of legs ; /, natural length of 



spider. 

 Fit/. 2. a, nest in piece of bark ; b, another nest in groove of a piece of 



wood ; c, lid of nest detached, showing the inner side. 



XLIII. — On the true Nature of the so-called " Bathybius," and 

 its alleged Function in the Nutrition of the Protozoa. By 

 G. C. Wallich, M.D. 



At no previous period in the history of deep-sea research had 

 a more boldly conceived, but, as I venture to think, more un- 

 tenable doctrine, been offered for acceptance by the scientific 

 public, than when the alleged discovery of this extraordinary 

 Protozoon was formally announced by Prof. Huxley. 



In 1868 this distinguished biologist published an elaborate 

 paper " On some Organisms from great depths in the North 

 Atlantic," in which he expressed the opinion that certain 

 masses of protoplasmic matter, found in specimens of deep-sea 

 mud which had been submitted to him for examination in 

 1857, constitute a new phase of living being, to which he 

 gave the name of " Bathybius.' 1 '' In referring to this subject in 

 their first " Preliminary Report on Deep-sea Dredgings," 

 published just afterwards in the ' Proceedings of the Royal 

 Society,' viz. in Dec. 1868, Drs. Carpenter and Wyville 

 Thomson say that " the examination which Prof. Huxley 

 has been good enough to make of the peculiarly viscid mud 

 brought up in our last dredging at the depth of 650 fathoms, 



