ZOOLOOY AND BOTANT, MICROSCOPY, ETC, 385 



Remarkable Polychset Parasite. *^M. Caullerj and F.Mesnil have 

 found a case of the unusual parasitism described by Saint-Joseph of 

 Labrorostratus parasiticus S.J. (a Eunicid) inside Odontosyllis denostoma 

 Clap, (a Syllid). The specimen was found on the LithotJuminion zone at 

 Saint-Martin. The parasite extended along the greater part of its 

 host's body, and seemed to be nearly adult, though without visible 

 germ-cells. As Saint-Joseph has shown, the Eunicid- passes out when 

 adult and becomes sexual in free life. This is to be compared with 

 what occurs in Monstrillida? and entomophagous insects. The parasite 

 does not differ much from free Eunicids. Five similar cases of parasitic 

 Eunicids have been recorded : — ? Lumbrironereis sp. in Marphysa 

 sangvmea, Oligognathus boneUise in Bonellia viridis, Haematodeptes 

 terebeUidis in TerebelJides sfromi, Oligognathus parasiticus in Spio 

 mecznikovianus, and Labidognathus jyarasiticus in a Terebellid. 



Profuse Liberation of Spermatozoa in Lithothamnion Zone.f — 

 F. Mesnil and M. Caullery observed on the evening of August 18, l'J15, 

 a widespread milkiness in the pools of the Lithothamnion littoral zone. 

 This was due to a profuse discharge of spermatozoa, and their attention 

 was first of all directed to large mature specimens of Audouinia 

 tentacuJata Mont. Further investigation showed, however, that the 

 spermatozoa which caused the milkiness were more like those of 

 Lysidice ninetta, which also occurred in the locality. When ripe 

 specimens of Lysidice are disturbed they often burst into pieces as they 

 swim off, liberating the reproductive cells in a fashion somewhat 

 like that of the Palolo worm. It is probaljle that the milkiness was due 

 to Lysidice. 



New Species of Polycirrus.J — M. Caullery describes Polycirrus 

 (Leucariste) arenivorus sp. n. from Saint-Martin, an interesting form 

 that makes a U-shaped tube, like that of the lobworm, in very fine sand. 

 It has very long whitish tentacles, a yellowish thorax, a colourless 

 abdomen. It eats tlie sand and autotomizes readily below the tenth 

 segment. It is frequently infected externally by a remarkable Copepod 

 Xenocmloma brumpti Caull. et Mesnil. 



Development of Stratiodrilus. §— W. A. Haswell has made a 

 contribution— practically the first — to the embryology of the Histriob- 

 dellida3. There is no metamorphosis. Segmentation is complete, but 

 unequal, and resembles closely the corresponding process in the Rotifera. 

 At an early stage in segmentation one of the cells ceases to take part 

 in the process of division and becomes converted into a mass of non- 

 nucleated finely granular material (secondary yolk), which remains 

 distinct till a late stage. A large vegetal cell at one pole becomes 

 immersed among the neighbouring cells, and the cells to which it gives 

 rise in the interior of the embryo probably represent, in part at least, 



* Bull. Soc. Zool. France, xl. (1915) pp. 160-1 (1 fig.). 



t Bull. Soc. Zool. France., xl. (1915) pp. 198-200 (2 figs.). 



X Bull. Snc. Zool. France, xl (1916) pp. 239-48. 



§ Quart. Journ. Micr. Sci., Ixi. (1916) pp. -301-12 (1 pi. and 4 figs.). 



