44 Mr. J. C. Pearce on the Embryo of an Ichthyosaurus. 



and margins having 8t tinge of red. Legs long, robust, provided 

 with hairs and sessile spines ; fourth pair the longest, then the 

 first, third pair the shortest ; they are of a reddish brown colour. 

 Each tarsus is terminated by three claws ; the two superior ones 

 are curved and pectinated, and the inferior one is inflected near 

 its base, on each side of which are two or three fine teeth. The 

 palpi resemble the legs in colour. Abdomen oviform, thickly 

 covered with hairs, convex above, projecting over the base of the 

 cephalo-thorax ; along the middle of the upper part extends a 

 broad, dentated, yellowish brown band, on each side of which is 

 a brownish black band ; sides and under part yellowish brown ; 

 the former is spotted with brownish black, and a broad, dark 

 brown band extends along the middle of the latter. Superior 

 spinners long, slender, hairy, with the spinning-tubes disposed 

 along the under side of the terminal joint. The sexual organs 

 exhibit an orifice having a red-brown margin. Plates of the 

 spiracles dull yellow. The body and limbs are supplied with 

 numerous compound, sessile hairs. 



The male is smaller than the female, but resembles her in co- 

 lour and in the relative length of its legs. The cubital and ra- 

 dial joints of the palpi are short ; the former is not provided with 

 an apophysis, but the latter has a large, obtuse one at its ante- 

 rior extremity, on the outer side ; the digital joint is oval, but 

 elongated, the extremity being slender and compact ; it is con- 

 vex and hairy externally, concave within, comprising the palpal 

 organs, which are highly developed, complicated in structure, 

 with a large, spiral spine, brownish black on the outer and pale 

 yellow on the inner side, which is very prominent and recurved 

 at its extremity, and a strong, dark reddish brown process at the 

 outer side projecting beyond the margin of the digital joint. 



I have named this handsome species in compliment to Richard 

 Potter, Esq., M.A., Queen^s College, Cambridge, and Professor 

 of Natural Philosophy in University College, London, through 

 whose friendly zeal in promoting my zoological researches I have 

 been supplied not only with the spiders introduced to notice in 

 these pages, but also with numerous specimens of British species. 



[To be continued.] 

 ->vlt Yd h'TfoWnify rry.r! :»-r;.! t/-;:' ^' '-,!t '■.-*t,:-3--2;T^ t' t^ ir; |um 



Ylil?-^Notice of what appears to be the Embryo of an Ichthyb- 

 ' 'sauriit^ m the Pelvic cavity of Ichthyosaurus (communis?)^' 

 By J. Chaning Pearce, F.G.S., M.K.C.S. 



In developing an Ichthyosaurus which I took up from the rock 

 in the brown laminated lias clay of Somersetshire, and having 

 reversed the animal so as to lay bare that surface which was 



