30 MR. M. LATJBIE ON" THE 



different form. Over the rest of the body the hypodermis con- 

 sists of somewhat flattened cells with circular nuclei, but in the 

 region of this caudal organ the cells are columnar with large 

 oval nuclei. In one dissection I thought I could trace a nerve 

 to these cells, but I could not be certain. The appearance of 

 these columnar cells suggests a sense-organ rather than a gland, 

 and indeed we have found the stink-gland to be an entirely 

 different structure. What sense this organ serves is, however, 

 not so clear. It is almost certainly not an organ of sight, as 

 there is no pigment in or around the cells and the overlying 

 cuticle shows no modification for any optical purpose. It is 

 probably then either auditory, olfactory, or for the sense of tem- 

 perature, as are the lyriform organs of Spiders according to 

 Gaubert *, but which must be left undecided until the minute 

 structure can be investigated on properly preserved material and 

 experiments made on the live animal. 



II. Some Embryos op Fhrynus. 



While examining the Pedipalpi in the British Museum col- 

 lection, Mr. Pocock directed my attention to a few specimens of 

 JPhrynus which had embryos attached to them. Inasmuch as 

 practically nothing is known of the development of these forms t, 

 it seemed well worth while to examine what embryos there were, 

 though the number of specimens and state of preservation were 

 evidently not such as to make anything approaching a satisfactory 

 account possible. Through the kindness of Dr. Griinther I have 

 been able to cut sections through four stages, and have made out 

 a few points which are, I think, not devoid of interest. Unfor- 

 tunately, two of the four stages were too badly preserved to show 

 anything, so my results are based on two somewhat late stages. 



The development of Phrynus takes place, not, as usually stated, 

 within the mother, but the embryos are carried in a sac formed 

 of dark brown transparent gelatinous-looking material attached 

 to the ventral surface of the mother (PI. V. fig. 18). The abdomen 

 is concave on the ventral surface where this sac is present, and the 

 dorso-ventral measurement is so much reduced that it seems a 

 question how the organs necessary for existence can be contained 



* Ann. Sci. Nat. ser. 7, vol. xiii. 



t Bruce, Johns Hopkins University Circulars, vol. vi. 1886, describes only 

 a few points, and that without figures. 



