i8 93 . NOTES AND COMMENTS. 421 



knowledge by showing that in Orthoceras erraticum the siphuncle 

 moved, during the growth of the shell, from one side to the other, 

 while the siphuncular tube became less annular and more cylindrical. 

 Similar movement of the siphuncle is known in coiled Ammonoidea, 

 and may be accounted for by the coiling ; but one fails to see its 

 meaning in a straight and regularly conical shell. 



Another curious instance of variation in Cephalopoda is recorded 

 by A. Appellof (Bergens Museums Aarbog for 1892, p. 14, just pub- 

 lished). In all Octopoda one of the arms, usually the third on the 

 right, undergoes a peculiar modification for reproductive purposes, 

 which is known as " Hectocotylisation." In a specimen of Eledone 

 cirrhosa, Dr. Appellof has found the third arm on the left also similarly 

 affected, without, however, any corresponding duplication of the 

 genital opening. 



The clever sketches called " Zigzags at the Zoo," published in 

 recent numbers of the Strand Magazine, are above the average. We 

 do not remember to have seen anything more funny than the drowning 

 of the two bluebottles by the rhinoceros, " Tom." Mr. J. A. Shepperd 

 has exactly caught the flap of the ears, and his drawings are full of 

 suggestion and life. The comparison of the racoons to a couple of 

 well-known music-hall " artistes," if not in the highest degree 

 scientific, has a sense of humour doubly dear to one whose wits have 

 been much muddled by ponderous verbosity ; while no one, after 

 laughing over the illustration, will fail to remember that " These 

 animals bite." 



Ax elaborate memoir, entitled " A Contribution to the History of 

 the Geology of the Borough of Leicester," by Mr. Montagu Browne, 

 has been published by the Leicester Literary and Philosophical 

 Society (Trans., vol. iii., pp. 123-240). It contains a very full account 

 of all that is known about the Keuper and Rhaetic Beds, the Lower 

 Lias, and the Glacial Drifts ; with notes on the Water Supply. The 

 Palaeontological Tables enumerate the fossils found in the several 

 formations in the district, including the " derived " specimens 

 obtained from the Boulder Clay, and those found in Pleistocene 

 valley-gravels and more recent deposits. The authorities for each 

 record are noted by means of a somewhat complicated system of 

 symbols. 



An* excellent account of the Geology of Dublin and its neighbour- 

 hood, from the pen of Professor W. J. Sollas, appears in the Proceedings 

 of the Geologists' Association (vol. xiii., pp. 91-122). It is well illustrated, 

 and was intended as a guide to the members of the Association who 

 visited Dublin and Wicklow last July. 



