296 



Part III. — Seventh Annual Jtyport 



bearing ova in many cases. Calanus finmarcliicus appeared in limited 

 numbers, whereas none were observed the previous month. Centropages 

 typicus, Pseudocalanus elongatus, and Longipedia coronata were common. 

 Oithona spinifrons occurred more sparingly. Eradne nordmanni (amongst 

 the Cladocera), was less frequent than in the previous month, but the 

 reproductive activity of the examples was uot diminished. A few 

 examples of the Cypris- stage of Cirripedes occurred in most hauls of the 

 net. Other forms obtained were exuviae of Balant, Atylus Sivammer- 

 damii (frequently), Podocerus capillatus, Diastylis Rathkii, Cuma with 

 ova, a few examples of My sis fiexuosa, chiefly young. Nauplii occurred 

 throughout the entire period, aud were often numerous. Zoeae of various 

 kinds, including the long-spined zoeae of Porcellana, and larval Norway 

 lobsters occasionally appeared, but they were comparatively few. 



The crustacean contents of the surface-net most nearly resembled those 

 of the bottom-net, showing that these two regions of the water were most 

 affected by this group. Halitemora longicornis and Acartia longiremis 

 (some of the females still bearing ova), were as numerous as in the former 

 net, and Calanus finmarcliicus was also abundant. Longipedia coronata 

 occurred occasionally in considerable numbers, while Centrojpages hamotus 

 and Oithona. spinifrons were less common. Nauplii were very plentiful 

 in this net, but Eradne, though appearing almost daily, was in limited 

 numbers, some, however, presenting young in the brood-pouch. A few 

 larval cirripedes (Cypris-st&ge), were generally obtained. Zoeae of 

 PortuttW and other forms, the long-spined zoeae of Porcellana, with some 

 crabs in the Megalops-st&xe, were also captured, along with a few young crabs 

 from T l F to J inch, the larger size of these generally being a feature of the 

 month. Some seemed to pertain to Corystes. Atylus Swammerdamii 

 and Podocerus capnllatus were also obtained. 



The mid-water net gave a larger number of the smaller forms than in 

 August.* Thus Halitemora longicornis and Acartia longiremis were 

 numerous, while a few examples of Pseudocalanus elongatm were also 

 met with. Zoeae of Portunus and other forms occurred on most occasions, 

 the long-spined larvae of Porcellana being frequent. Young crabs from 

 to \ inch were also abundant, the earlier forms presenting the 

 large eyes of the Afegalops-st&ge. Atylus swammerdamii, Hyperia medu- 

 sarum, Podocerus capillatus, Idotea tricuspidata, a young shrimp 7 mm., 

 Pandalus annulicornis 9 mm., and a few examples of My sis fiexuosa 

 completed the list. 



The pelagic Crustacea of September are, therefore, both varied and 

 numeious. 



In the bottom-net throughout September young bivalves in the pelagic 

 condition were uniformly present in every haul, though they did not occur 

 in profusion. Amongst these the chief place was held by young mussels, 

 which varied from -012 to '014 of an inch as a rule, an occasional 

 example inch or more (2*5 mm.) in its long diameter also being found, 

 as in a large collection on the 15th. Such, however, may have been swept 

 by the net from other floating structures. On the 22nd some very small 

 bivalves '008 inch were present, but they more resembled the young of 

 other mollusks, many of which were present amongst the mussels. Besides 

 the bivalves numerous minute univalves were obtained. Such seemed to 

 be the young of various forms abounding in the Bay, such as Natica, 

 Velutina, and others. These pelagic univalves form a conspicuous feature 

 in the fauna of the season, and they swim about as actively as the per- 

 manently pelagic forms, such as the young of Spirialis. 



* It is right to state that a new mid-water net may have had some relation to this 

 condition. 



