THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[FOURTH SERIES.] 



No. 62. FEBRUARY 1873. 



XI. — Summary of Zdblogical Observations made at Naples in 

 the pointer of 1871-72. By E. Ray Lankester, M.A., 

 Fellow and Lecturer of Exeter College, Oxford. 



My chief object during a recent stay of some months in Naples 

 was to commence a study of the general and histological de- 

 velopment of Mollusca, with the view of ascertaining what 

 significance is to be attributed to the various parts of their 

 organization in the light of the "germ-layer theory," recently 

 extended with such convincing force by the admirable obser- 

 vations of Kowalewsky from the Vertebrata to various groups 

 of lower animals, such as the Vermes and the Insects. 



I propose now to give a very short statement of some of 

 these observations, as well as of others made on some of the 

 innumerable interesting forms of marine invertebrates with 

 which the invaluable fishermen of Santa Lucia provided me. 



Development of Loligo. 



Since the time of Kolliker (1837) no contribution has been 

 made to our knowledge of the development of Cephalopoda. A 

 short note by Mecznikow on Sepiola contains very little and is 

 not illustrated. I obtained eggs of Loligo first in January, and 

 subsequently with tolerable regularity until April : they are 

 better adapted for observation than those of Sepia. 



The structure of the ovary is very similar to that of a bird. 

 The branched ovary contains eggs of all sizes enclosed in vas- 

 cular capsules. The basketwork marking seen on the ovarian 

 Q,gg is not a plication of the proper capsule, but of the surface 

 of the vitellus, where it is in contact with the inner cellular 

 lining of the capsule^ which sends deeply penetrating ridges and 



Ann. & Mag. N. Hist. Ser, 4. Vol. xi. 6 



