304 Prof. M'Intosli's ^'otesfyom the 



length, and the mature form has from twenty-four to twenty- 

 eight segments, the surface being beset with pa[)ill8e and 

 encrusted with sand and mud, a feature which enabled 

 Dr. Allen to separate it from S. hijstrix found along with it. 

 The dorsal cirri are short, with enlarged bases, so as almost 

 to be pear-shaped, aud there are two thick anal cirri. The 

 pharynx lias a tooth anteriorly and the proveiitriculus has 

 tea rows of glands. The dorsal bristles are simple, slightly 

 curved at the tip. The terminal process of the ventral 

 bristles is somewhat long with a curved end and spikes ; 

 moreover, the end of the shaft is dilated, with a process in 

 front. 



Laugerhans found two males with swimming-bristles and 

 sperms. A female carried eggs on segments 12-15, whilst 

 another had on its ventral cirri either ova or embryos. The 

 f male had no swimming-bristles. He thought that it 

 aj)proached S. pirifera and 6'. hystrix, but the great size 

 of the palpi and the shape of the median tentacle are 

 characteristic. 



This species is entered in the list from Plymouth, but 

 some uncertaint) exists, though it may yet be found on the 

 southern coasts. As mentioned on page 159 of vol. ii. 

 Part I. of the Monograph, Dr. Allen's preparation showed 

 that the structure of the foot, the presence of a single 

 slightly curved and pointed bristle, and the structure of the 

 compound bristles all agree with S. hystrix. The example 

 from Plymouth did not show the spine on the enlarged 

 terminal region of the shaft as figured by Langerhans. 



In connection with the Syllids the recent interesting 

 remarks of MM. Caullery and Mesnil* on viviparity and 

 })artlienogenesis may be mentioned. They found a form, 

 Ehlersia nepiotocaf, sp. n., amongst Lithothamnion at La 

 Hague, Avith young at different stages of development and 

 to the number of a dozen in the ccelom — and without traces 

 of any male or of hermaphroditism. They are inclined to 

 suppose that in certain forms of these and other Syllids a 

 life-cycle occurs, in which, after normal reproduction, par- 

 thenogenesis takes place, as in Aphides and Cecidomya in 

 some generations. A consideral)le number (over a dozen) 

 have been added to the British Fauna lately, and more will 

 probably yet be found by a further minute search of shore 

 and sea. 



* Compt. Rend. t. 16.'i, p. 75G (1916). 

 t v>j7rios, young, aud roxos-, viviparous. 



