ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 579 



from the intestine of manatees. We may refer to one of the points 

 noted. It is in regard to the way in which these parasites attach them- 

 selves to the mucous membrane of the caecum. The ventral sucker has 

 such energetic suctorial power that the mucosa forms a sort of hernia 

 into the interior of the sucker and completely fills it. 



Incertae Sedis. 



Weldonia parayguensis.* — G. H. Martin describes an animal super- 

 ficially like Microstoma lineare, but which could not be satisfactorily 

 referred to any accepted group of Turbellaria. Each consists of two or 

 three zooids, one behind the other. A large mouth opens into a 

 pharynx, with compHcated folds ; then follows an intestinal region ; 

 there is no trace of an anus. A very interesting feature is a deep 

 groove along the whole length, above the nerve-cord. The nerve-cord 

 during the greater part of its length consists of a much flattened tube. 

 At the anterior end of each individual the nerve-cord turns upwards 

 and comes into contact with the wall of the neural groove. It also 

 gives rise by short lateral stalks to two large ganglia, which surround on 

 each side a sensory invagination of the epidermis lying on the neural 

 side of the pharynx. The pharynx of the younger buds is found on 

 the apo-neural side of the animal, as an inpushing of the epidermis, 

 which in later buds comes into communication with the intestine on its 

 apo-neural side. Against any close connection with Turbellarians the 

 author notes the presence of a cuticle, the apparent absence of cilia, 

 the relations and structure of the nervous system. Perhaps, he says, 

 there is some approach to an extremely early Chordate. 



Rotifera. 



Parasitic Rotifer in Rhizopod.j — E. Penard gives a description and 

 figure of Proales latruncidus sp. n., which lives parasitically within and 

 on the Heliozoon Acanthocystis turfacea. The small Rotifer, about 90 //. 

 in size, allows itself to be ingulfed in the usual Rhizopod fashion by 

 its unsuspecting host, but no sooner has the envelope closed upon the 

 Rotifer, than it expands its ciliary wreath and proceeds to eat up every- 

 thing it can find in the larder, then it attacks the protoplasmic walls and 

 feeds on these. A terrible struggle now goes on between the host and its 

 prey, which usually lasts about six hours and nearly always ends with 

 the death of the Rhizopod. "When the Proales has fed sufficiently and 

 Acanthocystis has given up the struggle, it begins to lay eggs, one to 

 three in number, and then it seems to consider that it is time to get out 

 of its prison, for it proceeds to push, bite and hammer at a selected spot 

 until the thick wall and plates give way and the little Rotifer can escape 

 in the open. The eggs mature in about 24 hours and the young escape 

 through the opening made by the parent, in order to repeat this re- 

 markable life-history. In the summer of 1904 Dr. Penard found nearly 

 half of all the Acanthocystis turfacea afflicted with this parasite, a 

 regular plague for these Rhizopods. 



* Zool. Anzeig.,xxxii. (1908) pp. 758-63 (5 figs.). 

 + Mikrokosinos, ii. (1909) pp. 135-143 (7 figs.). 



