60 



SCIENCE. 



[N. S. Vol. VIII. No. 185. 



Bwim about like an excited Nereis limbata 

 and finally fasten to one of the females 

 with his jaw. Throughout the latter por- 

 tion of the month Aidohjtus was taken in 

 abundance. On May 17th swarms of Ter- 

 rebellids were observed to migrate from the 

 clusters of Parypha, brought to the labora- 

 tory from Quick's Hole, and to gather on 

 the sides of the aquaria. Lepidonotus bred 

 throughout the first half of the month, and 

 ripe females have been found as early as 

 April 25th. Dr. Mead informs me that if 

 the females are captured during the day 

 they will deposit their eggs at about 6 p. m. 

 The ripe females are generally greenish 

 drab on the lower side, while the males are 

 pinkish white. If the stagnant water, in 

 which the animals have been retained dur- 

 ing the day, is replaced by fresh sea- water 

 the eggs or sperm will be seen to leave the 

 nephridial openings of the posterior two- 

 thirds of the body in streams. Since the 

 eggs after fertilization settle to the bottom, 

 the water may be renewed without diffi- 

 culty. The embryos swim in from eight to 

 ten hours and the gastrula stage is reached 

 in about twenty hours. Harmothoe, found 

 in the same localities as Lepidonotus, from 

 which it is distinguished by having eigh- 

 teen rather than twelve pairs of scales, 

 breeds about one week earlier. The eggs 

 may be secured and fertilized in the same 

 way as those of Lepidonotus. The ripe 

 females are bright pink on the lower side. 

 Dr. Mead found Seolecolepis viridis and 

 Clymenella torquata breeding during the early 

 part of May. The eggs of the former species 

 are found in the sand-tubes ; those of the 

 latter are very'large, but difficult to secure 

 because of the shortness of the breeding 

 season. Specimens absolutely ripe extrude 

 the eggs in confinement, but if not abso- 

 lutely ripe the eggs degenerate without be- 

 ing extruded. Nereis limbata was found 

 swimming on the surface on the ISth- 

 Spirorhis breeds during May, and the fully 



formed embryos may be shaken from the 

 Fucus, to which the adults are attached. 

 Fine large egg-bearing specimens of Sagitta 

 were abundant until the middle of the 

 month. 



Dr. E. G. Gardiner reports that the small 

 acoelous planarian, Polychcerus caudatus, was 

 repeatedly found, that several examples of 

 a large species of Monotus, collected near 

 the Laboratory, laid thousands of eggs upon 

 the walls of the glass jars in which they 

 were confined, and that Plagiostomum freely 

 laid in captivity. He also found great 

 numbers of Dinophilus. 



Mollusks. — The squid {Loligo pealii) made 

 their appearance on May 7th, when several 

 hundred were taken at Hadley Harbor. 

 Many eggs in early stages of development 

 were found, and the animals occasionally 

 laid in the aquaria. Artificial fertilization is 

 easily accomplished. Many squid were 

 taken throughout the month, and one egg- 

 mass found attached to a fish trap filled a 

 large bucket. TJrosalpinx was found breed- 

 ing on the 21st. The sand-collars ofLunatia 

 were frequently brought into the Labora- 

 tory, and naked mollusks often deposited 

 their eggs in the aquaria. 



Echinoderms. — On May 10th Eehinar- 

 aehniusparma showed no sign of exhaustion ; 

 larv£e of Cribrella were taken in the tow- 

 net, and the Ophiurans, abundant at North 

 Falmouth, contained only immature eggs. 

 An earlier note, made at N'ahant, reports 

 Ophiopholis as ripe May 20, 1893. 



Coalenterates . — -Pleurobrachia rhododaetyla 

 was not abundant. The reproductive ele- 

 ments were found to be ripe by Dr. 

 McMurrich towards the end of May, 1890. 

 Berce was taken at ISTewport, E. I., on May 

 7, 1896, and at Bristol, E. I., on May 

 15th. Mnemiopsis and Cyanea arctica were 

 only occasionally found. The planulfe of 

 the latter may be easily raised in the Lab- 

 oi'atory. They attach themselves in from 

 seven to ten days after the eggs have left 



