104 Prof. M'Intosh's Notes from the 



and in the Forth — generally in the bottom-net by day, for it 

 is curious that none have yet been obtained in the surface- 

 nets at night. Besides the points already mentioned, it may 

 be stated that the labial tentacles were pale and the odonto- 

 phore, which often projected outwards, was yellowish. The 

 adult Clione of our shores would appear to be much smaller 

 than tliat of the Arctic Ocean, for the largest obtained were 

 only about 10 or 12 millim. In regard to the occurrence of an 

 example at Falmouth, Pelsener * seems to think this remark- 

 able, from its southern position. Boas f also is of opinion 

 that it is mainly limited to the Arctic seas, though examples 

 have been found at Portland, Maine, by Gould, and on the 

 west coast of Norway by Sars. 



Though Hermann Fol's beautiful memoir | on the develop- 

 ment of the Pteropoda includes Clione aurantiaca^ yet he 

 does not give the intermediate stages between the shell- 

 bearing period and that with the lateral fins, and the shajje 

 of this species differs considerably. The early stages of 

 Clione limacina, indeed, seem to have been rarely met with, 

 for Pelsener § adds little to the descriptions of Boas |i, and yet 

 the latter figures only a stage in which the lateral fins are 

 present with the three rings of cilia. 



On the 3rd of November, 1897, several examples of a larval 

 nioUusk (PI. II. fig. 1) were captured in the bottom-nets. 

 Each showed a head-segment with a ring of cilia (non- 

 continuous) in front of the odontophore, a large median 

 region of the body with a central ring of cilia, and a median 

 (alimentary) region with many yolk-globules, and, lastly, a 

 ring of cilia posteriorly, with the pygidium behind. In the 

 figure the otocyst is indicated. In another example (PI. II. 

 fig. 2) a row of large globules (yolk?) occurred in front of 

 the median ring of cilia, the size, regularity, and refraction 

 of which were striking features. In these specimens the 

 epidermis is clearly differentiated from the deeper layers. 

 The odontophore and the teeth of the lateral sacs are shown 

 in PL II. fig. 7. The teeth at this stage of development 

 seem to be incomplete, as no median series is present. The 

 lateral eversible sacs, however, have a formidable armature. 

 These young larvae were evidently the product of eggs dis- 

 charged by adults in the neighbourhood. 



As the mollusk grows older the body becomes more elon- 



* Pteropoda of the ' Challenger,' p. 47 (1887). 



t " Spolia Atlantica." 



t Archiv. Zool. Exper. iv. (1875). 



§ Pteropoda of the ' Challenger,' p. 47 (1887). 



II " Spolia Atlantica,"' ^'idensk. Selsk. Skr. Kiobenhavn, 1886. 



