266 THE BIOLOGY OF THE SEA-SHORE 



sandy coils of Arenicola on the 2nd March, the stalk of the 

 cocoon passing 2 or 3 inches into the sand. M'Intosh 

 (19 1 5) states that numerous pale green gelatinous masses 

 about the size of a gooseberry were found by fishermen 

 digging for lug-worms on the 3rd of May ; they usually 

 had a strand of mucus at one end. Williamson (19 16) 

 has kept a number of Arenicola in captivity and has obtained 

 several green capsules which, however, appeared somewhat 

 smaller than those usually found on the beach. The spawn, 

 with one or two trailing strands of mucus, was found 

 adhering to the sides of the box, which seemed to indicate 

 that the worms were swimming about during oviposition. 



The cocoons of Scoloplos armiger have been found by 

 Hornell {op. cit.) in close proximity to the adult worm, on a 

 sandy beach at Egremont (2nd March), and by Cunningham 

 and Ramage (1888) in the estuary of the Forth (February). 

 According to the first-named writer, they are small, gela- 

 tinous, pear-shaped and brownish in colour, smaller than 

 the green masses of Arenicola, and are anchored amongst the 

 bare ripple-furrows of the sand, the cylindrical stalk descend- 

 ing two or three inches into the sand. Cunningham and 

 Ramage describe them as gelatinous and transparent with 

 opaque white eggs and embryos. Garstang gives February 

 as the breeding season for this species at Plymouth. 



Oviposition in Ophelia radiata has been observed by 

 Cosmovici (quoted by M'Intosh, 1915) ; O. Bnacina is 

 not uncommon near low- water mark on British shores, and 

 no doubt the spawning habits of the two species are not very 

 dissimilar. The animals first envelop themselves in a 

 mass of sticky mucus within which the eggs are deposited. 

 The animal next withdraws, leaving a rounded mass with 

 a long tubular process. In Spio the spawn forms a flattened 

 tubular mass, 10-16 mm. in length, with a delicate envelope. 

 The eggs are in one layer or in several layers, each layer with 

 about a dozen longitudinal rows. Their colour is from 

 yellowish white to slightly orange. 



Orton {op. cit.) has obtained a good deal of material 

 with regard to the growth rate of various Annelids, especially 



