St. Andrews Marine Laboratory. 177 



(paleolae) of Sahellaria spinulosa and Harmothoe imhncata 

 were common in the bottom-net. Tomopteris about half- 

 grown occurred in midwater-, bottom-, and surface-nets. If 

 there was any diiference in size it was in favour of those from 

 the bottom-nets. 



The Chaetognaths were extremely abundant, especially in 

 the midwater-net, and many were almost mature. The larger 

 forms in this net measured 1^ incli, and some of the same 

 size were seen in the other nets. Besides the Trematode 

 parasite several showed a larval Trematode in front of the 

 caudal septum. 



The same forms were found in March so far as it was 

 possible to examine during the intervals of storms. Many of 

 the littoral Polynoidee continued fully ripe, such as Harmo- 

 thoe, Evarne, and Lepidonotus. Though it is known that 

 certain of the Nemerteans spawn at this time, no lai'val forms 

 occurred in the tow-nets, in which they seem to be rarely 

 found. 



Amongst the Annelids in April were also Autolytus pro- 

 lifer and the epitocous form of Nereis {Ijphinereis) . The 

 former bred freely in the laboratory and their variations in 

 colour were noteworthy. Viewed from the dorsum many 

 females are pinkish with dark brown eyes. The ovigerous 

 region is reddish and green, the former cliiefly characterizing 

 the segment-junctions. The succeeding region is greenish in 

 front, pale posteriorly, Ventrally the colours are similar but 

 fainter. The alimentary canal has a dull yellowish coat. 

 The coloration of the ova and embryos in the sac in some 

 cases is pale, in others dull yellowish or greenish. The 

 young after emergence agreed with the descriptions of pre- 

 vious authors, and appeared to be more elongated than the 

 larval examples of Autolytus cornutus of Alex. Agassiz * 

 before the tentacles appeared. Agassiz found his forms in 

 April. The reproductive period of A.prolifer in this country 

 is prolonged. 



No example of Alitta virens was procured in any of the 

 nets ; yet the beach in former years in March and April 

 has often been strewn with splendid examples, some more 

 than 3 feet in length. They would therefore not seem to be 

 so characteristically pelagic at the reproductive season as 

 Palolo, the Syllidians, or other Nereids. 



Tomopteris was frequent and of fair size (1 inch), while 

 the Chaetognaths were on the whole less conspicuous than in 

 the previous month, though some reached f inch long. A 



* " On Alternate Generat. in Annel.," Journ. Bost. Soc. Nat. Hist. vii. 

 p. 392. 



