312 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



The early part of September brought unsettled weather, 

 and with it a general diminution in the number of organ- 

 isms present in the tow-nettings. With the exception of 

 Nauplii, very few larval forms were seen. On the 15th a 

 single specimen of the free-swimming Polychsete, Gattiola 

 fiiimarcliica, was taken. Oikopleura attained its maximum 

 numbers at the end of this month. 



Early in October large numbers of Pelagia perla 

 appeared in the Bay, and with them Pleurobrachia and 

 Hormiphora reappeared, as also did the Radiolarians noted 

 in January and February. Sagitta and Oikopleura were 

 again common on the 18th. Two specimens of the 

 trochophore represented on Plate VI. (fig. 2) were seen on 

 the 28th, when post-larval stages of two Polychaetes were 

 common. Molluscan veligers and Lamellibranch fry were 

 present in small numbers on the same date. 



The November tow-nettings revealed a marked increase 

 in the numbers of Diatoms and Molluscan and Tunicate 

 larvae. The gastrulating blastospheres represented on 

 Plate VII. (figs. 2 and 3) appeared towards the end of the 

 month, as did two stages of the Holothurian larva (fig. 1). 



In December the gastrulating blastospheres just men- 

 tioned increased in numbers, but no further stages of 

 their development were seen ; and the Holothurian larva 

 again occurred. Sagitta was represented on the 17th and 

 30th by two or three specimens. Several specimens of 

 the trochophore represented on Plate VI. (fig. 3) were noted 

 on the latter date. Post-larval stages of four species of 

 Polychaeta had each a few representatives. 



Comparison of the foregoing summary with that con- 

 tained in the Eleventh Annual Report, already cited, 

 shows that, in the main, the various organisms appear 

 and disappear about the same times year after year. 



Finally, we print a complete list of the organisms found 



