782 report — 1884. 



of which the shell surface is covered, hut between the hases of these. The megalo- 

 pores and micropores lodging the organs of touch are arranged in vertical parallel 

 lines with great regularity, the large pores occurring at intervals in the lines of 

 smaller pores. The eyes are present in enormous numbers, the anterior shell alone 

 hearing more than 3,000, and the entire eight shells more than 11,500. 



In Tonicia mannorata the eyes are arranged in single straight radiating rows, 

 on the anterior and posterior shell. On each lateral area of the intermediate 

 shells there are from two to four similar rows of eyes. In Onithochiton the eyes 

 are disposed somewhat similarly. 



In the genus Chiton, eyes appear to he entirely ahsent. though the touch organ 

 of two sizes and corresponding pores are present. In Molpalia, Maugina, Lorica, 

 and Ischnochiton, I have as yet detected no eyes. In Chitonellus there are no 

 eves, and the supply of touch organs is scanty and confined to the margins of the 

 tegmenta. 



The arrangement and structure of the eyes and organs of touch will prohahly 

 he of great value in the classification of the Chitonidse, which has hitherto proved 

 so difficult a prohlem. 



No traces of any structures resemhling the eyes and touch oigans of the Chito- 

 nidse can he detected in the shells of Patella or allied genera. The tegmentary 

 part of the shells of this group appears to he something sui generis, entirely unre- 

 presented in other Mollusca. Its principal function seems to be to act as a secure 

 protection to a most extensive and complicated sensory apparatus which in the 

 Chitonidse takes the place of the ordinary organs of vision and touch present in other 

 odontophora, and fully accounts physiologically for the absence of these latter in 

 them. 



Dr. W. B. Carpenter observed the perforate structure of the tegmentum in 

 Chiton, though he did not examine the nature of the contained soft network. The 

 late Dr. Gray, in his well-known paper on the structure of Chitons, recognised the 

 fact that the tegmentum in the Chitonidre is something peculiar to the shells of this 

 family. 



Since the above was written, the author had his attention drawn to a memoir 

 by Dr. W. Marshall, in which the tubulate structure of the tegmentum of the shells 

 of Chitonidse is described, and to papers by J. F. Van Bemmelen, in which the 

 papilliform bodies which occupy these in Chiton margmapis are described and 

 figured. These memoirs are referred to fully in an extended and illustrated memoir 

 on the present subject, published in the ' Quarterly Journal of Microscopical 

 Science,' for January 1885. The eyes appear to have entirely escaped the obser- 

 vation of naturalists hitherto. 



10. On the Structure and Arrangement of the Feathers in the Dodo. 

 By Professor H. 1ST. Moseley, LL.D., F.B.S. 



Professor Moseley 's observations were made on the only existing specimen of 

 the skin of the bird, namely, that covering the head belonging to the Oxford 

 University Museum. The feathers differ from those in all other birds in being 

 arranged in groups of three. This peculiarity is shown in the well-known old oil 

 paintings of the Dodo. The homologues of the lateral feathers in each group of 

 three are to be sought in the two minute filo-plumes which spring from the sheath 

 of each feather at its base, one on either side in modern pigeons. An illustrated 

 paper on this subject will be communicated to the Zoological Society in the spring 

 of 1885. 



11. On the Presence in the Enteropnensta of a structure comparable with 

 the Notochord of the Chordata. By William Bate son. 



12. A Contribution to our Knowledge of the Phytopti. 

 By Professor P. McMuerick. 



