68 ARENICOLA MARINA. 



A single worm of good size will make bait for four or six hooks, each piece being 

 broken off and fixed on the hook. The fingers appear to suffer much from friction and 

 the secretion in this work, and soon bleed. It has been found that by dipping the 

 fingers in a solution of alum this injury is avoided. 



Habits. — The sides of the burrows are stained with the yellowish-green exudation. 

 The sand is ejected from the anus, forming a spiral coil on the surface, and near it 

 is a wide hole, from which the anterior end is protruded when the tide is full, though 

 Dr. Johnston states that it is the posterior end. The worm is usually about a foot 

 below the surface at low water. 



Reproduction. — M. Sars (1845) described the grass-green eggs of what he considered 

 to be Arenicola enveloped in mucus, and he noticed segmentation and hatching of the 

 young (with red eyes) which he figures. They occurred in February and March at a 

 depth of some feet, adhering to Zostera and Fuci. The relationship of these to Arenicola, 

 however, is uncertain. 



Max Schultze 1 in 1856 detailed the development, prefacing it with a general 

 account of Annelidan growth, yet the roseate gelatinous masses, with a long pedicle of 

 mucus, which he procured at Cuxhaven, appear to belong to Scaloplos armiger, or a 

 similar species, the bristles especially differing from those of Arenicola. 



Cunningham and Ramage (1888) found similar gelatinous cocoons in the Forth in 

 February, the jelly being translucent and the ova and embryos white. As their larvae 

 had two anal cirri, they thought they pertained to Scoloplos armiger. They state that the 

 genital products are shed in the Forth in August and September. They observe that 

 transverse mesenteries are only present in the four anterior somites, and here they are 

 incomplete. A septum occurs between the buccal and the first bristled segment, none 

 between the first and the second bristled segments. One lies behind the second and one 

 behind the third bristled segment. 



Hornell (1891) again, describes the large green pear-shaped egg-masses associated 

 with the sandy coils of Arenicola on the 2nd of March, the stalk of the cocoon passing 

 2 or 3 in. into the sand, and he made observations on the development. 



The littoral forms breed from the end of February to the end of April, and again 

 from July to September (Ashworth). 



The reproductive cells occur immediately behind the posterior portion of the nephro- 

 stome, but not on the first pair— thus only five pairs of gonads are present (Gamble and 

 Ashworth) . 



The genital products escape by the last five pairs of segmental organs, some by the 

 first pair also, and the ova are often caught by the mucus surrounding the worm. The ova 

 are 0"16 mm. in diameter, and have a distinct but thin vitelline membrane (Gamble and 

 Ashworth). 



Numerous pale green gelatinous masses about the size of a small gooseberry were 

 found by the fishermen digging for lobworms on the 3rd of May, usually with a long 

 strand of mucus at one end. The eggs appear to have been deposited since the previous 

 day as none were then found, and they are early eggs, being about the thirty-two cell stage. 

 They evidently develop with rapidity. The capsule is firm and elastic. Next day (4th) 

 1 Vide also a short notice in the ' Zeitschr. f. wiss. Zool./ Bd. iv, p. 192, 1852. 



