ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 577 



spongicola lives within Monaxonid sponges ; Richardina spinicincta, the 

 only representative of the Stenopidea yet found in British waters, seems 

 restricted to the areas peopled by the Hexactinellid sponge Pheronema ; 

 Leontocaris lar has only been found on two occasions, and in each haul 

 Antipatharians and colonies of Lophohelia occurred abundantly. We do 

 not quite follow the author when he says : " This, coupled with the 

 highly specialized structure of the species, suggests the possibility of an 

 A Icyonarian associa t ion . ' ' 



Of the 54 species of Decapoda Xatantia from British and Irish 

 waters, 19 have been found north of the Arctic circle, while 26 occur in 

 the Mediterranean. 



Five species of British and Irish Nantautia (four of which have not 

 been found south of Scotland) are known to live on the bottom in water 

 below freezing-point. These are Pandalus borealis, Spironiocaris polaris, 

 S. spinus, S. gaimardi, Sabinea sarsi. 



Snapping Shrimps.'* — Henri Coutiere deals with about thirty species 

 and varieties of Synalpheus from the American coasts. He divides them 

 into four groups, and discusses their relationships and distribution. A 

 striking fact is the existence of forms almost identical in regions so 

 remote as the Red Sea and California or Florida. For the Synalpheids 

 are very sedentary animals, which are almost never seen to swim, but 

 live in couples in Sponges and Madrepores. Many such facts suggest 

 the idea of species primitively widely dispersed. Coutiere finds nothing 

 analogous to the mutations which Bouvier has described among Atyidse. 



Annulata. 



Regeneration in Oligochaets.t — F. H. Krecker deals with phenomena 

 of regeneration in Limnodrilus, Tubifex, Lumbriadus, and Lumbricus. 

 Limnodrilus does not regenerate a head when more than seven somites 

 have been removed. An interesting point brought out is the small 

 amount of new tissue regenerated at the anterior end. No individual 

 replaced more than one-and-a-half segments, which was the case when 

 the first three somites were removed, and the entire amount removed 

 was regenerated only when the first somite alone had been cut off. 



Although lack of movements proper to the head end may prevent 

 the worm (Limnodrilus) from burrowing when the anterior segments 

 have been removed posterior to the level at which a head regenerates, 

 still it seems probable that it is also in part due to the important fact 

 that the bluntness of the anterior end in this region prevents the worm 

 from cleaving its way into the mud. For Limnodrilus the minimal 

 size of a piece, at different levels within the head-forming region capable 

 of regeneration, is as follows. A head-piece will not regenerate unless 

 it consists of at least 7 somites. At the level of the second somite the 

 minimal piece is also 7 somites, 2-8. At the level of the third somite 

 it is 5 somites, 3-7. At the level of the fourth somite it is 4-7. At 

 the level of the fifth somite it is 3 somites, 5-7. This is the shortest 

 piece of this worm capable of regenerating at both the anterior and the 



* Proc. U.S. Nat. Museum, xxxvi. (1909) pp. 1-93 (54 figs.). 

 t Zeitschr. wins. Zool., xcv. (1910) pp. 383-450 (3 pis.). 



