192 TBANSACTIONS LIVEEPOOL BIOLOGICAL SOCIETY. 



be called off occasionally to other duties. During the 

 first fourteen weeks the number of gatherings received 

 out of the possible six were — 5, 6, 4, 3, 4, 2, 3, 4, 4, 3, 3, 

 5, 3, 4. 



These gatherings, which have been worked up fully, 

 bring the record up to the end of April. The rest of the 

 collection, which is now in process of being examined, con- 

 sists of some sixty tubes, giving an average of nearly 

 two a week for the remainder of the year. Taking 

 these statistics, along with the many previous less com- 

 plete records that we have, extending back for ten or twelve 

 years, there are some prominent features of the collections, 

 looking at them week by week and month by month, that 

 arrest attention — the abundance of Sagitta in January 

 and February ; the comparative scarcity of Copepoda early 

 in the year ; the abundance of diatoms, such as Biddul- 

 phia, Coscinodiscus, Bhizosohnia, and Chcetoceros, in 

 February and early spring; the appearance of Nauplei 

 and then other larval forms in February and March ; 

 the comparative scarcity of plankton all round in February 

 and March (except when gelatinous Algae sometimes 

 swarm in the latter month) ; its increase in April, 

 and especially the increased abundance of pelagic Coel- 

 enterates and of Copepoda in early summer ; the appear- 

 ance of fish eggs and embryos and larval fish in abundance 

 about Easter ; the disappearance of Nauplei and other 

 larvae as summer goes on, and the great increase in Medusae 

 and Ctenophora ; the quantities of Oikopleura which appear 

 in the height of the summer ; the abundance of Dino- 

 flagellates in late summer and autumn ; the great relative 

 abundance of life in general during July, August, and 

 September ; and lastly, the rapid diminution in the 

 amount and variety of plankton during the last few 

 months of the year, 



